You are right about Future being runny. What I have done when treating the windows in a kit is to attach the window in some way to a clip that is then put into a mount that will hold the windows upright. As you pointed out, it does run and rather than have it drip all over everything or run down the mounting, I'll use a paper towel to just touch the bottom edge of the window. The Future product running off will go onto the towel and be wicked away.