I was told to use copper spray gasket on those. bad idea. These gaskets are actually reusable, but if you sprayed them with copper or any rtv you wont be able to reuse them because they'll peel when taken off.
I'd install them straight-up. When I redid mine, I got a new set(because they peeled when I took them out due to the spray copper) and I've reused them a few times with zero leaks (using stage 8 fasteners).