For anyone thinking of using Latex paint on their Piet - I screwed a test panel to a fence post three years ago facing true South. The panel was covered with medium weight fabric attached with Poly Fiber "Poly-Tak" cement. One half was finished with one coat of Poly-Brush and three coats of Sherwin Williams yellow gloss exterior house paint (the second from the highest quality grade), the other half was painted with four coats of latex only (all brushed on). I live in Colorado which has over 300 sunny days a year at 6700' MSL. That results in about 25% more UV radiation than at sea level. Anyhow, a punch test was done a couple of weeks ago on both halves of the panel, with the following results.

The side with one coat Poly-Brush and three coats of latex - three punches went through at around 80.