Darren, while the Rush is a great ball, I don't think it quite has the motor or cover to do true heavies....medium heavies....oh yeah....especially at 600 grit...
I'd go with either an Oracle drilled to ROLL, or the RS-X the same.....both at 600...pin below...cg out......maybe a rev-leverage hole....
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JEFF
"Chance to squint at a sky so blue that it hurts your eyes just to look at it."