Not sure this really answers your question, but it is my two cents on a Track ball I really like, the Uprising.
I too am pretty much a stroker. The Uprising absolutely kills the THS where I am (I had 722 last night with it). I like the Uprising because I think it is a little less squirty than some of the similar pearl stuff I have thrown, including the Black Widow Pearl. With its OOB finish, it still gets down the lane plenty, and absolutely snaps at the backend. Carry is great.
I haven't thrown a 505C, so I am not quite sure where the Uprising would fit compared to that, but if are looking for a more predictable skid/snap ball, I would grab an Uprising. I don't really use the Uprising on any heavy oil shots, so maybe someone out there can comment on whether a surface change to the Uprising will make it work on heavier oil.
299 - Roto SD-73 Classic
299 - Elite Black Label
298 - Roto SD-73
297 - Brunswick C 3.5
290 - Roto Rogue Cell