I say to use both forms. On THS, you do not need to be quite as accurate to score well. That is why you typically see the bowlers with higher rev rates average the highest.
On tournament conditions, that will call for more accuracy. So, I would tone down the speed and revs because it is those guys that tend to struggle a little more because they do not have the area on the lane and more often than not, cannot create the area in order to score.
EX: I use 2 hands obviously as my normal release. HOWEVER.....I practice every once in awhile putting my thumb back in the ball and rolling it the right way. If the lanes are dry enough, I may need to put my thumb back in the ball and kill the revs on it to keep the ball more in play.
Since you are able to use both forms, practice regularly using both. It makes you more versatile to lane conditions. You'll be glad you did.
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Steven Vance
Former Pro Shop Operator
If anyone out there is worried about the scores being too high, try duckpin!!