Steve,
Do you plan to do some polishing as the final stage?
A friend of mine used diamond lapping paste when modifying his EQ6 (from ebay,
http://cgi.ebay.com.au/12-pcs-5gram-...item51962bab92).
The end results are fantastic in terms of PE - it was reduced from 30arcsec pp down to 7 arcsec pp, see here:
http://tech.groups.yahoo.com/group/EQMOD/message/26509
http://groups.yahoo.com/group/EQMOD/...25881/pic/list