Bill,
This grease plate method works pretty well. You can just use any kind of metal plate, it doesn't need to be that thick and the plastic sheet between them isn't necessary either. Just two metal sheets, aluminum or steel .125" or thicker with a good coating of grease between them is great. I like to make the bottom plate a couple inches larger than the top, and make sure the edges of the top plate are well deburred. Place one under each main gear and load the aircraft with the same weight you would like the wheels to align with. They will change angle slightly with load. I like to go toward the heavy side of where I think the plane will be most of the time since the tires will wear more under greater load anyway.

Matthew Collier
Fibercraft Inc.