Just thought I would interject here.......
I have just painted my small rib. I bought the Hypalon Paint (quite expensive), and put it on with a small radiator roller, after doing the edges with a 1" brush.
I over rolled the brushed paint with the roller to get rid of brush marks,and the result is very good.
It turned out MUCH BETTER than I expected, and doesn't look like it's been painted.
I can only speak for the WHITE paint, but it now looks like a new boat to me, look for yourself..............