There really is only two ways of throwing the ball coming up the back of it or coming around the ball.

I use the Jaros style release coming up the back of the ball and you can stroke it smooth which Jaros does or crank it. But don't think Jaros can't rev it up. In fact, he revs it up pretty hard but is so smooth just looks like he's sroking it but depends on the conditions. Last I saw him on the Shark he was putting more on it and was reving it up pretty good but was nothing compared to other bowlers with the same release. Eugene McCune for example uses the same release but obviously more violent and can crank the tar out of it. Wes Mallot uses the same release, so does Norm Duke, walter Ray Williams Jr.....

I got to see Jaros's release up close and he really keeps his swing loose and is able to get a good handful smoothly so it just looks like he is just a plain ol stroker but he is much more then that. If you want to see him more of a tweener in my opinion, look at his 90's videos how he used to snap his backswing behind his head. Then years ago after struggling a bit he used the same release but kept his follow through straight up in the air to get a smoother roll. Parker Bohn also went to this type of follow through. Difference between the obvious sides of the lanes is Parker comes around the ball and Jaros comes up the back of the ball.