Hey bigfish,
Try the 400-600 then add magic shine to that. As mentioned before in another thread, it's very important what grit you use under a polish that really affects how much friction a ball can create. Personally from my Haus machine, I use 2 grits of sanding but only use the finer grit(about 800) when the balls are designed to go longer or are made for drier conditions. Try this and see if it helps...
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Rick Leong
Ten Pins Pro Shop
Track Intl. - Amateur/Pro Shop Staff
Vise Inserts Staff