I tend to forego food in favour of champagne tbh, as I get bloated too quickly if I mix food and booze.

I've managed six small glasses of champagne in GC on my first trip from T5 (roughly equivalent to 1 bottle), with the missus matching me drink for drink, followed up with a couple on board.

I've also managed 4 wee bottles of Pommery on a LHR-DUS flight before, with the final bit being drained as the jetway was being attached (from a plastic glass by that stage).

However, when I'm guested into the F lounge I tend not to count what I'm pouring myself.