^ Wut? After a day or two of tweaking tolerance kicks in HARD. The first few hits are pure ecstasy... by the second day it's just tweaky, residual stimulation.
Just remember that tolerance to monoamine releasing drugs sets in VERY fast, basically as soon as you start feeling the drug. You should be taking a main "attack" dose, dosing too low at the start will make you waste quite a bit. After you get your original rush, just redose as you see fit. The longer you wait from your original dose, the less effective it will be. Also if meth is anything like MDMA (it is), redosing so late into the experience will drastically increase neurotoxicity. Not a good thing.
Obviously you don't want to dose anywhere CLOSE to 6 hours before you try to sleep, and it's best to try and eat before you take anything because after you dose there's no way you're going to be eating. For myself I take a larger dose in the beginning, and redose every hour or two to keep my peak going. I usually only redose once or twice in a day, beyond that and you're just causing unnecessary damage and probably wasting quite a bit of speed as well.