The tartan 30 I bought this year has a newly sealed and painted bottom. The surveyor told me that when I go to paint to just go right over the old coat. Do I need to clean first and with what? No sanding at all or what? Also It is sitting in a cradle and I'm not sure on how to get the spots where the jackstands are or near the bottom of the keel. Appreciate any advice. Also how much paint would I need and how much does it cost?