Avoid alcohol before bed. In any quantity. It is incredibly disruptive to sleep cycles. You will fall asleep, but quality is not good. There is a reason many studies use it to disrupt REM.
Extremely apparent too. It'll put me out real fast, but I'll be awake in a few hours and then repeat a few more times till the sun is up and you gave a splitting headache.
I think you need a couple hours per unit (a 5% ABV beer, etc). You have ti have fully processed the alcohol and given your brain chemicals a little time to settle down. So you could conceivably drink a few beers or glasses of wine during the day and stop in the early evening and be mostly fine. But right before bed if it hits your first sleep cycle it is kind of a disaster because the whole first cycle alpha, to beta or however it sequences gets messed up and a lot of people float between REM and deep sleep without getting either in the first half of their sleep (assuming its 8 hours).
