Low doses sometimes dont even produce visuals, just different thought patterns and often alot of laughing, some people say it feels quite speedy too but not in my experience. Visuals like squigly lines, walls breathing, brighter colours.
High doses for me are a totally different ball game. Very different and often strange thought patterns and some quite astounding and sometimes scary visuals. Ive had amazing OEV's like trees growing from lifeless dirt right before my eyes, my hands turning into caveman hands, freckles on peoples faces jumping out at me and when I look in the mirror a beard growing from my hairless face.
Not all has been good though, Ive seen the shadow of an alien walking around my empty house and one time I had a really fucked up CEV, I pictured my mum's armless, legless torso and head hanging from a rope with satanic like symbols cut all over her body. That scared the fuck out of me but I soon forgot about it, its these sort of things you just have to tell yourself its not real and focus on something fun and enjoyable. Which can be very hard to do.
BTW I can not use a phone or any electronic device on high dose acid, im basically useless, just a body full of strange and usually magical thoughs, and lots of eye candy. So I advice staying away from things that involve much concentration....stay away from ovens too coz I know people who've started fires from trying to cook intoxicated and forgetting about stuff, driving ppffftt, I hope you know better than to drive on any intoxicant
If your worried and you want to take a high dose just make sure you have someone trusted and experienced because they can really help. Acid is tons of fun until you overdo it, then you will ruin it for yourself and you'll never want to do it again.
Have fun & be safe.