HEHE I have run into this problem as well. I tore down my 2 level 2X4, with the intentions of combining new grids with old ones to make a 2 level 2x5...... and lo and behold half way through construction I realize DOH! My grids don't match up!
I wound up having to stop my plans, and finish my cage off as a 4 level 2x3 for now. I am waiting until after the holidays when I can just purchase all new girds and build the cage I want.
I feel your pain!
http://www.guineapigcages.com/forum/...upid-idea.html