What grade of wet and dry paper to use?

While I am eagerly awaiting the arrival of my new old razor in the mail I have been giving some thought to the basic repair work I may have to do. I'm sure it will have some pitting and tarnish. I plan to get to it with wet and dry paper. So I was wondering if anyone could advise me as to what grade of paper I need to go with. I have a sheet of 120, 150 and also 400 laying around here somewhere. Is this appropriate, or do I need to find some finer stuff?
Thanks for any help you could give.

I have found 400 was a great place to start (although I was not trying to remove much pitting really just polish) then move up from there...

I start at 320 for polishing, all the way through the grit's to 1200. I'd go finer too if my tool shop had it. I just keep forgetting to get it from another source. It depends what finish your after though. Highly polished or satin?