Get your primer and paint from the same place, Try Brown Brothers in Glasgow. try and get 2 pack as its better for painting without a spray booth also you dont need to laqure 2 pack paint, I would go for a 6" da you'll b there all day with a 3" one, rub the hole lot down with p240 grit use scotch brite in the bits u cant get too with the sander, then prime, then p400 then p800 wet and dry watch u dont rub through the primer with the p400, if u want u can just skip the p400 and use p800 wet and dry but it will take longer.