I think you are ok with a 500 stone. I posted some pics of a forgecraft rehab I did a while back. 90% of the work was done with a 500 stone. I think too coarse isn't a great idea for a first time because you risk going too fast. Once that metal is gone...it's gone. Here are some before/after pics.
Nice work! Thanks, everyone.
I like to see a little patina/rust on any ODC knife I buy off the bay ever since I received what turned out to be a forgecraft knockoff. The blade felt like it was made out of aluminum, which was why it looked like it was in such good condition. Got a refund but it was pretty disappointing.