20 MA how much paint?
 

Not sure of the colors yet but some shade of white for the insides, console and gunnels. A different color for the sides and white for the bottom.

So how much primers, paint and other things do I need?

Your best bet is to check out the coverage on the type of paint you want to use...there is no easy answer. If you go to a store like Fiberlay they can get you going in the right direction.

I ended up using about a gallon of each color. As far as primer, that depends on how much body work you have to do before painting. Most paints can be applied directly to gel coat when properly sanded and de-waxed

Btw the cheapest place to buy paint in Miami is Premier Auto Supplies. They have 12 or 13 locations in Dade and Broward counties. At most locations they have someone knowledgeable enough to help out, however, it would be good if you speak Spanish as I have found they don't have a lot of English speaking help.