we just use 500 before applying 2-3 coats of 2pack paint. and for polishing up i use 1500 wet. try getting some of 3m's new fast cut. iirc the buffer we have at work is set to 1500-2000 rpm.. i can double check that tomorrow tho..

http://www.ebay.co.uk/itm/3M-Perfect...item1e66e71709