Im going to make my own frames. I bought 10 just to look and come up with a way to make them simple. I see the top is 1 inch wide from side to side. The sides start at 1.3/8" and drops down to 11/8" at the bottom. im thinking of just making a 1 inch frame all the way around. Is there a certain reason why the sides taper like they do. Or will making it all one size be ok?