HEY guys i’ve been teaching again now 4 yrs and i use both 6″ and 8″, (toppers) as some call them, all this time. we use an aluminum or nylon/glass master to put the steel laps on. i worked for crystalite/pacific test specialties from 68-77 and made the electroplated diamond laps, we were the first. i buy the china made diamond toppers off ebay and i must say THEY DON’T skimp on the diamond. far better than what we did as we measured the amount of diamond. i just cut a 43.6 carat topaz and most done on an 8″ 3000 i bought recently and i’m going to go back and get more of them, ones to be available to my club members. i also use ONLY 50,000 grit diamond powder on a TIN lap with WATER ONLY, no oils or greases, to polish and at a very slow speed. my 6″ diamond wheels have been costing me on average $4.50 to $6 for grits 80-3000, and 8″ $10-$14 each for 100-3000. the 3000 just cost me $11.50 and are holly terrors cutting action with fine finish. if you want to know who i get from contact me. my diamond powder cost me $80 for 1000cts and lasts a long time, 9 cents a carat, from china, seller— glass-polisher on ebay.