I may have asked this before but I searched and can't find it, if so. In the not too distant future I need to reinstall the rear glass in my GP. I am going to use urethane and need some of those little rubber blocks to keep the glass from sliding down while the urethane cures. I can't seem to find them. Any ideas what I can use? The one thought was little blocks of butyl take like originally held the glass in place, but those are nasty to trim to size. A rubber block would be easier to work with.