I've been using Roto for quite a while, but it's time for a new one and my pro-shop guy is recommending some Track stuff.  I'm open to suggestions but need to figure out which ball is the best fit with what I already have.

I'm a tweener, about 16-17mph at release, medium-medium high revs.  Generally bowl on a THS with medium oil.

Current Benchmark ball: Roto RSP.  Performs well but isn't extremely versatile.  Can't play a big swing because it won't come back.  Usually play this one toward the middle of the lane with a tighter line in the oil because it squirts at the first hint of the drier track area.

Second ball: Roto Sonic Boom.  Great ball for when lanes are drier.

Thinking my best option might be a 715C or 920T.  I'd like to have something that can get through the oil (unlike the Sonic Boom) and gives me the ability to pay a bigger swing when the tight line isn't there (unlike the RSP).  I'd like it to be a controllable reaction that doesn't squirt at the first hint of dry.