With sober vs non-sober I think it is partly in your head but also the biological effects of drinking alcohol do play a part. The more you drink, the more your senses become impaired (blurred vision, hearing difficulty etc), your reaction time slows (so much for that incredibly witty comeback to a joke), short-term memory loss, vomiting or general nausea, balance impairment and all the other wonderful prizes found at the bottom of the bottle. All of these things will make gaming more difficult; however you do get the increase of self-confidence, lowered inhibitions and things like that which can up your game.
When sober there are none of the issues and just your base confidence level, so why not work on increasing that base confidence level, to the point that drinking doesn't increase it anymore, because it's already so high? There is an argument to be said for drinking a little bit, for example recently when going out, I've set a maximum of 3 drinks limit. Why not just not drink at all? Because I like to drink, just generally, I like the taste and the sociability of having a chat with my mates over a pint; but I also know that I can have 3 beers and it doesn't noticeably affect my senses, reaction time, speech etc, any more than 3 and those things start cropping up one by one. I think that for your game to truly get to its 'peak', the beer has to be put down.
When gaming drunk and it doesn't go well, I think it will certainly be down to the drink to an extent, when sober there is no excuse, you have just gamed poorly and are able to recognise this, then learn from it.
As for the 'To fap or not to fap' debate, this is something I think is largely in the head. There's no doubting the logic behind no fapping, increased testosterone levels and all that; but ultimately it's something to lay blame on when things don't work out "I got blown out of that 2-set, not because I ran poor game, it's because I jacked it this morning and they could sense this."
Ejaculating though is important for the health of your prostate, at the moment I'm reducing my FPW count (faps per week

) but that's just a personal preference thing, rather than because I believe it'll cause me to have mad game at the end of the week. One thing it does do for me though, is increases my determination to get laid and slightly increases my general libido.