Thank your for the insights, Reed. I talked to Ken today on the phone, and he said that he recalled you mentioning at some point on this website that you felt that you got the best surface finish with your scrapers using the 600 grit, and that with the 600 the wood "comes off like glass." I couldn't find that, but I have been doing a lot of searching from previous posts on this topic and I've found a lot of your comments to be very useful because as someone with 80 and 350 grits, and now curious about 600 vs. 1000-grits, you've apparently addressed my concerns in the past. For example, in one of your previous posts you said:
"...for scraper burrs, there is no real difference in burr edges on scrapers for heavy roughing between the 80 or 180 grit wheels, and same for shear cuts on good sound wood, or wood with no or little figuring. The 600 grit, on both gouges and scrapes, well, the 1000 as well, leave edges that are excellent for fine finish cuts and cleaning up things on difficult woods, but not practical for heavy roughing as they just don't keep the edge as long as the coarser grits. I need to swap back and forth between 600 and 1000 a bunch of times to see if there is any significant difference in those edges for cleaner cuts. High shear angle still plays into the formula..."
Sounds like the 600-grit would certainly make a difference for me, but the difference between 600 and 1000 may be negligible.