Polishing Glass

Can anyone speak authoritatively on the subject of polishing glass with a hand polisher? What grits of diamond abrasives/pads/discs should be use, leading up to felt with Cerium Oxide? What RPMs with each grit/felt?  Once you've gotten a completely level surface at the lowest grit, roughly how long each step (each finer grit) should take?  Let's assume a six inch square, flat, 6mm thick piece of fused glass... Are there differences between opal and transparent glass?

Thanks so much!

PS: This assumes all polishing is wet, plenty of water to keep the glass cool...

E Pezzulich