This is a tip that I got from RJ from RJS Originals, Inc. when I ordered two heat deflectors, one for my wife's 883 Sportster Trike and one for my FlSTC Trike. Although I have not installed it yet, I know this will be a really good install and cheap to boot.
Harley used to have a metal seat pan under the seat, which kept the heat from reaching the riders, but a few years ago Harley changed the seat pan to a plastic one which does not.
RJ's tip is to use aluminum tape or aluminum foil, which you can get from a hardware store, to cover the underside of the plastic seat pan. He claims that the aluminum tape or the aluminum foil will reduce the heat under the seat from getting through the plastic to the riders.
I think this is a great tip from RJ and I thank him for it.
Urlawyer
Note: Cost of the aluminum tape roll at Home Dept. - $10.68 including tax. Enough to do 4 to 5 seat pans. I think I will put two layers of tape on the seat pans.