According to the HUD spec sheet the wire mesh goes over the plastic on their pool covers. This seems a little odd. When the plastic fills up with water it will just pull apart and fall into the pool. It seems like it would work better to put the plastic on top of the mesh and staple it down good. Any input on where you put the plastic?

There are probably many ways to cover a pool that would be better than HUD specs. I've always put the plastic under the wire mesh, just because that's how they want it. I wouldn't want to do it another way and risk not getting paid for it. If for some reason you're worried about the rain water, just put a slight slope on it so the rain will run to one side.