Thanks, Jay.
I have 3 quarts of spar exterior urethane so I can use them here.

John:
I bought 3 small cans of the General Finish MilkPaint and tried them out on some scraps. I like the ease of applying it and the bright colors. The cans were a little on the expensive side so maybe an exterior house paint will work, if I can find a "suitable" color.

This is a picture (from WOOD magazine) of what I'm building. It's all cut, screwed and glued and just needs a finish: