I'm trying to create curved window, using mostly simple patch meshes, so it would look like one solid piece of glass. I've created simple shader, using q3map_nonplanar and q3map_shadeangle 179, however it still has visible difference between two adjacent patches. Screenshots will help to understand this issue.

As you can see, there are two horizontal lines across window (that's where the two patches meet), and there is visible difference in texture alignment. What should I do? Recreating whole thing with brushes will take ages, and right now the window looks really awful. Should I change something in my shader file or even glass texture? I'm out of ideas, so I would be extremely grateful for any help.
Cheers.