You will know if you smoking enough, because you immediately not want to smoke more. Yes you do get a burn residue, if you smoke off phone some times the meth burns thru the foil in the last moment, Too much before heat before it is done releasing smoke, will vaporize very quickly. As far as dosages 50-100mg should be plenty, out if you experiment with your dosage little by little you will find your sweet spot for a hit, until you smoke enough you can't get as high as you want. Personally I wouldn't smoke more than once every 2.5 hours only because the effects last between 3-5+ hours. Only smoke for one night or two at most, other wise you are gonna tweak and burn through your stash and be missing a couple of days. Anything that pops up out of no where type of experience and will be too high to deal with the situation comfortably. nomad bloodbath