Lots of tests and experimenting with dipping in wax. I need bigger balloons, but have a top tip for trying this at home; when the balloon is dipped in the hot wax the air inside the balloon will expand and depending on how hard it has been blown up, how quick it is dipped and how hot the wax is, there is a real risk of the balloon exploding. My experience now tells me, that the wax is distributed well and evenly over the entire 2-3 meter radius surrounding the pot. The good news is though that the tiny droplets of wax set cold flying in air and one can clean it of easier than wax melted on to a surface.