Decided to go with the Rustoleum line.....and this is my first experience in buying paint other than rattle can.......First question: Do I really need bottom side paint for bottom? (bottom will be painted turquoise, 15 ft alum boat, small lakes, fresh water and mostly trailered)..second question: Where can I get Rustoleum Marine paint and have it mixed to a turquoise?... I'm located in Mid- Michigan 