I have several questions on the Kolner clays.First,should the clays be heated in a double boiler just like the traditional hide/clays?Next,can they be sprayed on?Will they stick to a couple of coats of sanding primer or would shellsc be better or no need for either?What is the best material to sand them with?(tack or sand paper)I have the colnasize and read its directions.You'd think the manufacturers would have put directions on their product(not colnasize)!!!HELP ANYONE,Thank you