I am spot on with Dave81644.
First thing out of my bag on a THS is a benchmark ball. Something smooth and controllable. Something I know how to adjust the other balls off of, so I am not guessing if and when I make a change.
I take a few shots to zero it in, then try a different ball (all during warm ups) to see if the other ball has a better look.
What other ball I try is dependent on the reaction of my medium hooking boring benchmark ball. If the lanes seem to be playing wetter, I go up, drier, will ball down.