For anyone interested, I've found this article that clearly explains the difference between the CIMA and FEPA grit-size grading system, along with a lot of info on how to choose which grades of wet and dry to use when going from a coarse regrinding to a polished finish. It also explains the difference in function between silicon carbide, aluminium oxide and aluminium zirconia papers.
http://www.woodcentral.com/cgi-bin/readarticle.pl?dir=shop&file=articles_244.shtml
http://www.woodcentral.com/cgi-bin/readarticle.pl?dir=shop&file=articles_244.shtml
