This lapping I did is with 240grit, 600grit, 800grit and 1200grit.
I lapped my stock amd phenom 955 heatsink cooler.
For some reason the center of the heatsink has a few scratches but around the center it is really good, I don't know why this happened because I took my time and I passed the heatsink over the wet and dry paper so many times but I coulden't get rid of the scratches in the middle.
It is very flat though now and my CPU holds on to the heatsink for like 2 seconds when I press the heatsink on my unlapped CPU.
Pretty good for a first try. I'd give an 8/10 as well, although that's about as much as I would do. Esp for a stock cooler. I would start with 400 to 500 grit and work up from there.
I usually do 500-800-1200-1500 or 2000 when I have some around. Then finish with wadding polish.
I'd give 8/10, think you've gone too hard on the lower grits I'm in the process of lapping an Athlon ii x2 250 and one of those coolers, not because its hot, but because it's going to be running for a long long time! and the cooler it is the less likely a failure is and lower the likelihood of my house burning down!!! Before temps - idle 41c, load 62c. Will post results when done