I know many disagree, but I do not find meth to be addictive. Cocaine yes. Alcohol yes. Nicotine, damn right. Opiates, sure. Meth? Hell no. About as much as cannibis. I want more, but there is no addictive crave that makes me want more. I'll use it if I have it, because I choose to. If I don't have it, I don't have it. Just like cannibis.
Much of the tolerance you describe is caused by sleep deprivation, dehydration, and poor nutrition--- not tolerance to the amphetamine. Get enough sleep,drink fluids, and EAT some food, and tolerance does not become a problem, even with long term use. Meth is not an addictive substance, absent he sleep deprivation or poor nutrition. You take more to make up for sleep deprivation, or poor nutrition, and it works for a short time, then you want more. You want more to make up for the sleep and nutrition deficits, not because you have a tolerance to meth.
When I run out, I get caught up on sleep. That's all. Takes at most a week without meth at all to catch up on sleep deprivation, as much as I can get caught up. I've slept as much as 14 hours a day for a week, and have slept for most all of three days several times. Once the sleep deprivation deficit is made up, the meth is as potent as ever.
I can take my top-quality product, sleep four hours a night, and stay on a run for weeks using no more than a gram a week. If the stuff isn't top of the line, good as it gets, I have to use more, sure. But the point is I can go for weeks on the same amount day in and day out if I get a base amount of sleep, stay hydrated, and eat.
If I don't sleep, eat, and drink fluids, it takes more and more of my product, of whatever quality, to keep me going. That isn't tolerance. Its sleep deprivation, poor nutrition, and dehydration.
Anyway, that's my take on it.
And I have had more than one monkey on my back before. So I do have a life-experience basis for the comments I make.