The last white car that I used a paste wax on, I used S100. Lately, I've been using Poorboy's EX-P on lights, but I haven't done another white car yet. I've done a number of gold ones though, they all came out great. Had a gold come out truly awesome with just FK1 Pink X2 over polished paint.
For an OTC wax, if you can't find a Harley dealership (they stock S100), get the new Mother's Reflections or FX Synwax. They're the coke to NXT's pepsi.