Just to add, I have done many a stupid thing with meth before and when you really cross the line into OD territory you know it.
My story is below and a bit long so for the quick answer my experienced conclusion on to much meth for one dose/day for my level of quality crystal is anything beyond 200mg per dose or per 12 hours period etc is to high. Normally id do 1g over 4-5 days and that would feel like a high dose, with all the high dose symptoms. A story below describes a time i took prob 400-500 orally, cause i was stupid, and the symptoms are unlike anything ive felt before.
Until you really cross the line, you often think other lesser negative symptoms that until then seem hardcore and really bad, indicate crossing the line, like bad anxiety or super fast heartbeat or visuals or bad vasoc, tingles, icy skin, paranoia etc. Many of those are caused by an extended binge, no sleep, dehydration and SNS stimulation buildup and has always occurred for me to some extent on every long and high dose binge.
But many find even those uncomfortable symptoms the normal and "safe" stuff that goes with the drug (at least as the word "safe" is defined by meths version of safe, which is not at all close to the same as the normal definition of safe).
However, in terms of taking a dose thats just to damn much, and those symptoms, that are not related to the above, those symptoms are very different from what i used to think taking to much felt like.
When I really crossed that line was when I made the mistake a few times of using crystal orally by shaking some shards out into my palm and eating them, while high and not having an ounce of responsibility in me, which is totally stupid since you cannot judge dosage like that, firstly since eyeballing is inaccurate generally and secondly because crystal comes in compact shards and when you eat un-crushed crystal it could seem like you are eating a really small amount but actually that "little" shard right there might possibly be a highly compressed pure dose close to 200mg or something, as an example. Ive crushed tiny shards into massive lines and doses before.
Anyways, when I fuked up a few times, you know instantly by a whole new level of symptoms clearly different from your usual high dose or long binge shitty symptoms, that are usually SNS build up related. The below experience was early on day two near the end of the first average dose, 12 hours after my first reasonable dose and about time for another. Was still already reasonably high, nothing hectic at all, average really, when I decided to eat a crystal shard that fell out of my baggie, that ive deduced to be about 400-500mg oral dose at least based on future and past experience, but will never really know for sure.
Anyways, 30 mins later when it kicked in...
Stage 1: As that dose that crosses the "real" line kicks in, you seem to instantly sober up, sort of come awake mentally and instantly realize something just happened and isn't right and that you prob "gon fukd up, dem be no doubt about it", when you instantly link your new state to your last dosage.
Super clarity and soberness blasting you out of your euphoric high into something that feels close to sober but is some wierd super focused insane level clarity of mind with your thoughts processing so fast you feel superhuman and beyond sober somehow.
At this point there is no anxiety or fear, or any major emotion really, just this pure clarity logic based mental state that makes it very clear that something has happened and its probably not good, but you dont feel any fear or actual anxiety, just logical awareness of the issue but dont feel enough to seriously consider you might be at real risk.
Then the chest sensations begin, wierd feelings in your chest area, flutterings, pressures, movements, its all just crazy sensations in that area you have never felt before. Its not like you feel pain or your heart beating fast or anything that can be identified by a normal person, its like your sensory perception of that area has broken and your getting random feedback. You cant even feel your heartbeat or tell what its doing in your chest at all, no matter how hard you try. You are cut off from that normal level of sensory perception regarding your physical state.
This feels similar to how different a full bladder can feel when really high, or on shrooms, where you often dont notice it until it gets really bad, its this strange feeling you need to consciously compute for a second before you realize what it means. Like that but worse.
All you know is that the area feels "weird" and for some reason you have gone beyond high into some kind of super high sober state and that its not good, not good at all, because logic is telling you that your last dose should make you more high, not sober you up. Fortunately no SNS type anxiety, paranoia, just pure logical unemotional concern, like a robot concerned it might be breaking, so you chill and calm down and wait to see what happens. Because you feel clear mentally you think its going to be ok.
2. Stage 2: Eventually at some point, after relaxing and monitoring the weirdness in your chest for maybe 1 hour, and otherwise generally feeling ok and still alive, and mentally stable, you think its all going to be ok. Logically you think, if its gonna get worse it would have already, it can only get better from here or stay the same, wait it out.
But then out of nowhere the opposite happens. Suddenly your mental state and performance plummets in the opposite extreme into what feels like a very drunk disoriented state, like you are really high on a bad weed trip, far to drunk to see properly, basically your mental faculties reduce by like 75%. Now this is scary as shit because you know that when a stim is literally doing the opposite of what its supposed to do and acting like a strong downer, sedative or bad anti histamine trip, something is not right. Still no SNS anxiety yet, just genuine logical concern.
The thing I can mention that most identifies this state and situation and that really freaked me out the most is that when looking at any specific location, basically wherever you are focusing on directly with your eyes, your peripheral vision (or rather your peripheral perception) is drastically reduced to a pin point and only where you are looking is "computable", perceivable and processable consciously. Everything else around you begins to very quickly vanish form your awareness or understanding, it stops existing eventually.
Now to be very clear, its not like your vision tunnels to where you focus, its more like everything but where you are looking at directly is not even comprehendable, noticeable, it doesn't exist, as if your brains awareness ability has been shot to shit and it can only process whatever you look at directly.
You know this is happening and it comes comes on fast but not instantly each time you change focus, and you know that there is stuff around you besides what you are looking at, but you dont know what exactly until you look elsewhere, where it then starts again and narrows in, scaring you again and you look elsewhere and get stuck in this situation of looking all over the place trying not to forget where you are and end up staring at the wall drooling and forgetting anything else around exists at all, forever.
It feels exactly like what I imagine it would feel like experiencing brain damage or a high drop in IQ or stroke or something and only being able to do one simple thing at a time and process only what you are directly looking at. I could think sorta clearly but perception was shot, or environmental awareness, if that make sense.
This was terrifying and lasted a while. The worst thing is you know your brain capacity has been reduced, its not like you are ignorant of it and therefore go with it, like perhaps with paranoia where you "dont know any better" at the time.
Nobody could explain what happened here or what could cause this physically, and I have never experienced it before after that stupid high oral dose of crystal. I think one mod mentioned it was likely the heart under serious stress or oxygen deprivation to the brain or something, or some kind of temporary stroke type situation, who knows. I would love to know exactly what was happening to cause such a contrary response from a stimulant.
Anyways, these days im paranoid and when I do give in and take, I'm so careful i build up with tiny lines over a much longer period. And will never take crystal orally again unless measured. Snorting seems much safer since you crush up the shards and can see exactly how much it is before you take it.