Andrew,
I had all kinds of problems with my VMania windows. I assume its not fitting with a hardtop (upper window gap). I adjusted my window sockets in the door, custom weatherstripped my hardtop, bent the windows some more for a better fit, trimmed the passenger window weather stripping to keep it from bowing out at the bottom, and put in a snap button on the window pillar with matching snap on the window strap because the velcro didn't work well. After all this its almost like having real windows.
The windows fit really well with the softtop, but were obviously a real pain with the hardtop. If I was to do it again, I would have sent Biff his windows back and bought northwind or the factory 96 windows. Biff backs up his products, but with these hand built cars sometimes they just don't fit right.
That said I think my windows look pretty good now and my car is almost weathertight. Its almost like having a car with real windows.
Dave