in my opinion 8 Hrs from bottle to throttle is not enough ,i am not sure if EK apply the 12 Hrs rule , why risk every thing just for the sake of it!
drink on your days off only !
Just a bit too paranoid for my liking, a couple of beers etc on a 24hr layover is never going to put you even close, but be warned you can and will be tested before leaving the hotel.
If you stick to lower volume alcoholic drinks you will never have a problem if you knock it off 12hrs before, unless of course you can consume faster than a professional darts player.