Need help with Window family

[rodneyf]

I have created this window family and most of it work great however, what I am trying to do is make this window add and subtract muntins as the width changes. I know I am missing something simple but my mind is a little scrambled trying to understand the conditional formulas and such. If someone would be so kind as to look at it and point me in the right direction that would be great. If it means I should create this family in a different way in order to accomplish what i'm looking for then let me know.

Thanks In Advance,