I didn't use anything on mine. The idea of the glycerin is just to make them slippery so they will go into the groves of the valve covers easier. But I had no problem putting them on dry. Just make sure the valve cover sealing surfaces and grooves are clean.
PS: You still need to put RTV at the half moon shapes at the back of the head and where the timing cover meets the valve cover. Don't confuse the RTV with the glycerin. I hope I didn't cofuse you more.
For Sale: M60B30 intake manifold, M50 intake manifold, 2.81 differential, new OEM upper control arm bushings, 8 M62 fuel injectors.