Hi Patrice! So glad you found the blog. My first advice would be to look at the original architectural drawings of your house to see the proportions used by the architect. I'm sure you have facade drawings in those plans. Even if you decide not to use muntins and do typical plain windows, I would do casements on your front facade and they would have to be 2 casements (vertical) side by side on each window opening. Would be happy to look at the drawings with you and give you my opinion.