[zzrv]

I put Velcro (the hook side) on both sides of the upper channel as per Carl Krueger's suggestion. I put the sticky side on the channel, not the glass. Makes the window a bit more snug in the channel, but not too much harder to slide. I'll be taking it out next week, so will let you know how it works.

P.S. Darby, there was NO weatherstripping in the channel to begin with.