Midi View Windows for double seam applications offer the best value for light requirements. They are a good balanced size and can be used conservation area as well as on new extensions. (a central glazing bar can be added if required for the extra heritage look) The overall structural opening for the window is 1075mm wide by 1008 high. For spacing purposes when using multiple windows the following guide should help when setting out the structure. For a single seam between windows the structural openings should be 500mm apart for the first seam. (same as the Mini) Then add 529mm for each seam required. For 2 seams the spacing between window openings would be 1029mm this would probably be your minimum spacing between windows.
If you would like to upgrade the Midi to triple glazed the extra cost would be £100.84. This is a good option if you were concerned about rain noise. The extra sheet of glass and the different thickness of glass in the middle work well to muffle the sound. You get a slightly better u value too.