cheech, I also have a Rival, it's drilled 4 1/4" x 4" pin under ring. I leave it at 2000 abralon. It's one of the better balls I've thrown for sure but I still run into over/under problems more often than not. I get a good midlane read and a hard arc out of this ball. For what it's worth, it flares about 2"(maybe a little more) I think for me with about 1/8" separation between the oil rings. This is next to the space between the fingers/thumb, not sure if that's the location you're supposed to measure the flare at.
I'm not saying I'm perfect but I do expect a little area even on sport patterns. Not sure if I should use weaker drillings, stronger drillings, more surface, etc. Again, the problem is not hook but just over/under, missing in a pinch results in hitting the face and missing out a board or two results in washouts or 2-8 variants. Sometimes it could be lane play which is my fault because one time I just moved in 10 boards and the pocket opened up, I had 3-4 boards at the breakpoint to strike and the worst thing I left playing there was weak 10s. This was on the Chameleon.
It sounds like around 5" pin to PAP for you is a good controllable reaction, in general. Being a little rev dominant, even with not so many revs you'd think that would work for me too.