If your have a fingertip-drilled ball, then a ball driller should be able to deduce your PAP for drilling future balls - that's already a good basis.
As one or two steps up, I'd recommend adding 2-3 balls, if you wnat to build an arsenal:
1) Consider a polyester spare ball, drilled fingertip. Great tool for corner pins and really dry lanes. Small investment, but IMHO the next best thing after an own pair of shoes.
Something stronger than your Tornado, which will be almost anything on the market. I'd look for mid-range balls (great value for money) with symmetric cores:
2) A ball with a low RG number, higher differential and a matte solid surface, drilled for smooth, early roll. This will be your oil ball, fro longer patterns. Balls that come to my mind are Storm's Furious or Brunswick's Copperhead or new Diamondback.
3) If the gap between Tornado and the matte ball is too big, and there's money at hand, consider a pearl reactive with a polsihed surface for medium condition, or as a ball to switch to when the matte piece runs dead. Medium RG and medium to high differential are IMO a good basis. Balls are (e.g.) Storm's Fast, Brunswick's Python or the recently discontinued Swarm, but other manufacturers also have options.
If you can afford the balls in a "package", you probably will get a good deal including the drilling.
Good luck!
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DizzyFugu - Reporting from Germany
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