Very useful article. Are there general rules for height to width proportions for double hung windows? We are going to replace our double hungs (6 over 6 light pattern) with a height to width of 1.8 with hopefully a slightly larger sized window, but with a 4 over 1 pattern. Do we want to keep 1.8 h to w? If we go wider the 4 lites on the top start to get a bit fatter.