I've done a lot of rubber seal glass installs on VW's over the years. Basically the same as the EB glass I just installed.
I have tried many lubricants and have settled on using Honda Motorcycle spray polish. This product is available at any motorcycle accessory store. It stays slippery, and does not dry out like dish soap or Windex. It cleans up easily when your done by just wiping it, no streaks. It is used for cleaning the bugs off of motorcycle windshields, and helmet visors. It safe and does not hurt any plastic, or painted items. It's a great general cleaner product for the shop.
John