Yul:

I generally lap before a session and that's that until a few sessions down the road but I only have one razor and don't do restoration work.

As to the flattening stone, some like it, some prefer the higher grit sandpaper but Lynn seems to find the flattening stone to be just right and he's gone through about 5 or 6 Nortons.

I think it will ultimately depend on you trying both and seeing which you preferr (sandpaper v. flattening stone).