I do not presently know the answers to your two questions; however, as someone else with an, as you say, overzealous metabolism, I will say that other substances behave... well, it depends. Caffeine doesn't really show an effect unless I consume at ridiculous speeds (i.e. half a can of Mountain Dew in three seconds, which made me super-twitchy for about five minutes), to provide something of a baseline. Alcohol hits fast, but if I'm not careful I can hit a hangover within a half-hour; as a result, it's very difficult to stay inebriated. Naturally, YMMV, but in case you ever do get curious, that information may help. (Not that I recommend it at all; I absolutely admit I'm an alcoholic when I can afford it.)