The biggest problem with modifying existing greases is knowing what's in the grease to begin with so you know what to add that will be compatible. A good synthetic base oil and a lot of thickener should do it. I don't know that any EP additives are really necessry, and I don't like calcium soaps. Good grease, not so good with the junk it leaves in a rifle barrel.
You mentioned Lucas, which reminded me about the "friction modifier" we discussed earlier. I have a variety of that stuff in the garage, from the various Mopar additives to the Ford stuff, and some BG and Winn's modifier, and of course the classic AC Delco limited slip additive. I wish I could tell you that it's an additive package that reverses the viscosity trend with regard to heat, but I don't think it is. Just stuff to keep the LS clutches from chattering on turns. I was always told that the Ford stuff was "sperm whale oil" and it might have been at one time, just a good film lubricant.
I wish I knew more about UHMWPE powder, I'll have to do some more research.
Gear