I would love to find a way to do it with out wrinkles. The problem with a shrink material is that the male mold has indentations in the crotch area and shrinking would bridge that. That's why i used the Vaseline which is sticky enough to hold the Seran wrap in place. One time I tried auto wax and put on several coats and the last coat was literally smudged on thick. I let the epoxy/glass harden over night. That was my first experience of panic since I could not get the seat off the mold. The tinniest fissure or imperfection in the mold will trap a drop of epoxy which turns to stone and the casting is locked on unless you "break" it free. I thought my mold was as smooth as glass too.