How far away from the thumb?
Here's why all the ??? I think USBC is trying to keep the pattern secret this year. It may mean they plan to change patterns during the tournament. You won't know what to expect until you start bowling.
That means you need an arsenal that can play on multiple patterns. The surface of your balls will represent about 85% of the reaction. The other 15% will come from the way the balls are drilled.
For example, my PAP is 6-3/16 over and down 3/8. My ball tracks right next to both my fingers and thumb. If I simply put the pin over my ring finger, it would be more than 6 inches from my PAP limiting the amount of flare/hook I might expect unless the lanes were dry. On the other hand, a person whose PAP is only 4.5 inches over, would have a 5 inch pin to PAP which might be what they want. A person who throws a spinner, would have a ball that would hardly break at all.
A nice 4 ball arsenal would be something really hard to shoot spares, then 3 other balls with varying cover-stocks and varying pin to PAP distances to control flare no matter what the pattern.
You wouldn't want to spend a lot of money going, only to find that all your balls react the same.
My current arsenal is four 14 pound balls. A Hy-Road drilled 60 x 3/38 x 30, a Lock drilled 50 x 5 x 50 and a Pitch Black drilled 50 x 5 x 30. Plus a plastic spare ball.
Hope this helps.