EVERYTHING varries with batch, weather, age of balls.
The only strategy is to drop the balls through. If you only have a big (for example) bore barrel then just buy cheaper brand paint, Diablo make all sorts of paint, but Hellfire is typically smaller than say Blaze, which is cheaper.
The best way to cope is to have a few barrels, that way you fit the barrel to the paint that is available rather than trying to dso it the other way round
Richard