I've just bought a pair of double louvered windows, which unfortunately are odd sizes. One measures 104 x 37 & is obviously too small, whilst the other measures 106 x 39 & rather than being screwed into the window hole on the bus, it looks as if it sits within a rubber seal as that's what it came with? Does anybody have any experience of these double louvres & also can you tell me what the smaller one fits?