Well since we are talking simply from experience, as far as your M2 principle, I do enjoy drinking and find that my muscles are fuller and I am leaner when I drink twice a week (usually 6-12 beers a night). Not sure if it is because I know I am going out so I train harder and diet better the days before or if it has to do with the beer itself(hell you never know).
I have quit drinking before for extended periods of time(usually because of bitchy girlfriends) and found no benefit to my phsysique. On the other hand there were times when I was drinking 4-6 times a week and was definetly not at my best looking then.
Take from it what you will, just my personal experience.