I'm very fond of high gloss UV-resistant Polyurethane lacquer. Technically it still yellows, you don't notice it and blocks a lot of the uv-rays.
The picture above is from a sculpture I'm coating. It's base material is a sort of epoxy that professionals use for making their carrier moulds.
I love the viscosity and the colour, but it turns out green very fast. (In months)
UV-resistant lacquer or varnish helps a lot. The gloss surface makes it easy to clean. :)