I wouldn’t really recommend polishing a yoyo after satining it. the point in satining is to make it better for grinding. the polish is just going to make it worse. But if you want to do it, go ahead. when I polished my 888, I just used terry cloth and a metal polish I had. worked pretty well, but it wasn’t really a mirror finish, just a shiny metal.
that’s what I use, works fine. I dunno if the rpms matter, but this one goes at 2900. which is great for making string, by the way. takes about 10 seconds of spinning, as opposed to almost a minute with my 600 rpm drill.