There is a lot to be careful about with the greaseless as it can put a hole in a full hollow quickly. Keep water close by if you use is and remember that with a lot of junk razors, you can end up with a shiny, unevenly flattened, pitted, but usable razor.
I like to follow the 600 greaseless with hand sanding from 320 up to around 1200 grit. Then I hit the black emory compound or a grey bar, followed by green, white and then a rouge sometimes. For me, the key to getting a mirror finish that you can count eye brow hairs in is to make sure you get all the deep scratches out. I really have found that the Matchless bars work the best for me on the compounds.
Have fun.