One inch high for every foot. So, if you have the 24 x 24 cage, the hardware cloth in the back of the cage floor should be 2 inches higher than the front.
The only reason I wouldn't use dividers, is that the cages will be crammed... with food and water. Not a whole lot of quaility space for the birds. Even the 30 x 36 cage would be tight with a food dish and waterer.
James.
Vickie, I would place the 1/2 x 1/2 over top of the 1/2 x 1. Be careful when you cut the 1/2 x 1/2. You will need some tin sheers, and some gloves. That glavanized hardware cloth will be sharp.
Only because I am jealous, are you building just one, or are you getting more than one with plans...