Think that people have to get rid of the fallacy of 8 hours bottle to throttle, and if it is as i think Carnage Matey stated before in his ops manual then should be removed as misleading if not downright dangerous.
I, to my shame got prosecuted for drink driving a few years ago, had been doing it and getting away with it for years, but when drinking excessively regularly as i was, became the norm, luckily had never been involved in an accident or hurt anybody during this period, just caught because of fog lights on.
In order to get my ban reduced i did a drink driving awareness course(very useful by the way) and was surprised by how much drinking can affect reactions and also how long it takes for alcohol to leave the system.
Metabolism,size, amount to eat etc, have absolutely no bearing on the level of alcohol in your breath or blood, another old wives tale.
The fact is that you lose 1 unit of alcohol consumed per hour, a small glass of wine is 2 units, an ordinary bitter or lager(Smiths,Fosters etc) 2 units, Premium lagers, Stella,Kronebourg etc 3 units.
So say for instance you have had previous to report for duty, only for instance 4 pints of Stella, not a huge amount by any means, and you are using the 8 hours bottle to throttle.
12 units drank, 8 hours off, 4 units still in the system at report time.
For driving the limit is 5 units, flying I believe considerably less, but it just shows that only a relatively small amount of drinking can have you over the limit if you use the 8 hour rule