1. Dont know, do a search for Oilmans posts, he details the pros and cons of different weights of oils
2. Seems reasonable around the Berkshire area. I paid about that for Dan Perkins to do mine.
3. Again, seems reasonable, I paid £75-80 for them off Dan Perkins
4. No idea, sorry, cant remember what my last P2 cost
5. ESR might still have some left, they are sending me some
PS What brakes you got