The grit jump between the 8K and the .5 micron is large in theory, but the paste works so quickly that it's not a problem. Some use a heavy layer of paste and do around 10 or so laps. My strop has a faint hint of ghostly green chromium oxide, and it does a great job with around 30 or 40 laps.
I have to agree with Randy about the chromium oxide, both that it's better than the .5 micron diamond paste and that you should get it from handamerican.com. :) I like agreeing with Randy; I usually find that when I don't, I'm wrong. :)
Josh