Get the Norton 4/8 by all means. As has often been said on here, the 8k edge is a good benchmark. You don't need anything else until you are getting consistently good shaves off that 8k side. That's how many of us got started. Many will then add the wonderful Nani 12, CrOx, etc. to refine their edges even further. Beyond that, you don't really need anything. It's just a matter of how much you want to spend on this hobby.