well there ya have it. Gambler deals with these issues everyday so I would stick there with the advice. I've only painted aluminum boats personally.
However, back to interlux products. (not an endorsement) Gambler, have you viewed these paints? I understand that PPG, house of color, dupont, sikkens, etc are primarily made as "automotive" paints but interlux is the mainstream brand of boat paint. They are huge and have many systems for different applications,i.e. top decking, hull paint, striping, etc. Could you (gambler) do us a favor and check their web site and give us a professional opinion from bassers point of view?
http://www.yachtpaint.com/usa/default.asp