I brew a little extra so I don't even come close to touching the true. Leave a bit of clear beer above it even. Wasteful? Maybe.
I also lose a bit at the bottom of a bottling bucket because the spigot is off the bottom. Sometimes I actually pour out the top of the bottling bucket to fill the last beer (marking it as a carb check).
Long story short, I get 50-52, usually. Two cases, two testers, maybe two for competition.