Is this actually good advice? A friend mentioned that a friend of his has been raging up the meth and I'm sure it's going to turn up at some point. After reading this thread, I'd like to have one really solid hit, rather than constantly re-dosing. I'd usually titrate up a new drug but I can't be arsed to be awake for a week.
I'm only 9 and a half stone, and generally seem to take fairly low doses of drugs (e.g. any more than 125mg of MDMA stops being fun and is way over-stimulating). Is there a sort of guideline, approximate meth to MD equivalence? I would like to be off my tits, but I don't want to have a heart attack.
125mg is fairly low for an overstimulation threshold for MDMA - my sweet spot is not much higher, at around 150mg, but I can take about 250mg straddling fun and discomfort, and still enjoy the experience. Over that and the experience is seriously affected by adverse effects to the point of being unpleasant.
If 30mg did little or nothing, then putting 50mg is sound advice. If it's your first time trying it, then probably not. If you are inexperienced, without a tolerance, and enjoy MDMA at doses lower than average, then I would advise against it - if it's pure, and crystalline methamphetamine usually is quite pure (at least compared to most street drugs), 50mg could easily be a little too much.
One solid hit is better than redosing which is still better than smoking too much and being awake for 3 days in psychosis. Assuming high purity, efficient smoking technique, and your tolerance, I'd try 20-30mg. It's quite subjective too, though - what some people consider rushing, tweaking, or pronounced euphoric effects, is overstimulation for others. I typically like to use stimulants at levels closer to threshold than excess, but if you're looking to just give it a shot, I'd imagine you want some of the rushing too, not a high for rearranging your bookshelf and generally obsessive-compulsively being disorderly at home. Still, I think for a small person with low acute and natural tolerance, 30mg, if successfully inhaled, should give you an idea of what it's all about. Now, I don't know or have enough experience smoking meth to know how wasteful it generally is, but I have heard the doses are usually around the same as what users would inject, and extrapolating from there, I would guess that 30mg is probably a reasonable amount, 40mg possibly excessive.
Either way, I wouldn't rely too much on a plan which essentially reads "I want an off-my-tits, but not over-stimulating dose of a drug I have never tried before... In the first hit!" To ensure tits-off, you risk overstimulation, I'm afraid. I'd rather make sure of the safety department first and go from there. Also, the first hit is a good gauge of the drug's effects, as effects are usually more or less linear - twice the drug will yield twice the effect.
The best policy, I think, would be to find someone who's been smoking a fair bit of it, and with whom you can relate to one another's drug experiences with relative ease. Ask them how much they smoke for the kinds of effects you desire, and convert that to how much bigger/smaller their amphetamine (or MDMA, if you must, but I think amphetamine sulphate would be better suited) dose is than yours.
Finally, Erowid may have something on doses (although not all drugs do - cocaine, for instance, doesn't) ... It's not meant to be comparative, but seeing where your MDMA dose falls on their scale of threshold-strong might help you select a methamphetamine dose on the same crude scale.