Paint and such
your average big game... well... Fisrt big game I went to I shot 500 balls. But, then again, that's my normal day's usage. I'd estimate 1/2 to a case for a whole day's play, depending on how hardcore you go out there. I've shot 300 in a day before too, with a stock gun. THAT was a trip!
I play up front a lot, and I can conserve paint too. But, assume you'll shoot your normal ammount of paint, possibly doubled. You'll be playing all day, so you're in it for the long burn.
As far as turncoating, I don't think that the UK is up for scenarios yet. Big Games are another story...
-Tyger