I've used polycrylic on paper, thinned about 50% as mentioned on rcuniv. Initially it worked well. But after a short time the covering got extremely hard and brittle. The slightest bump would poke a hole.
I believe that is because all the stuff available as paints are formulated mainly as floor finishes. In fact, the most fuel proof one, Varathane, is labelled "diamond hard" which should be a clue.