I'm not sure which balls your local Ebonite Rep will have, but I can speak to the Demo day happenings since we had a Hammer Demo a while back at our shop.
All the balls are pre-drilled with various spans that go up to 5" and come in 1/8" increments. The finger holes are drilled downsized so the grips will hold in the finger holes without any glue. Your thumb is a predrilled threaded insert that comes in a various round sizes and 3 standard reverse pitches. Basically you will be able to get a ball that you can throw and should be close to your current ball, but not exact. I equate it to throwing a buddy's ball that kind of fits your hand.
I had a blast running one with my boss and the rest of the pro shop staff...it was even better being able to get out on the lanes. We are going to have an Ebonite Demo in September I think and I'm REALLY looking forward to that and trying out some of their newer offerings.
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-Chris: DJ's Pro Shop : Auburn, MA