You are ready to go on. At this point, you have probably trued up the shape of the surface to a sphere or very close to it. The most important thing when starting work on a diamond generated surface is to get all traces of the generation marks gone. Diamond generation leaves microscopic fractures in the surface. These must be completely removed before going on and it sounds like you have done that.

As to grit labeling, yes, there will be nothing larger than 80 grit in the batch. This isn't to important when working with 80 but becomes more and more critical as you progress through the finer grades. Good optical grade abrasives will always be very evenly graded. The grit supplied by lapidary suppliers is not nearly as well graded and should be avoided except for the coarse grades such as 80.

Jarvis Krumbein