Yes, 24x36 or 30x30 are preferable. I also prefer actual 1"x1/2" cage wire for the bottoms, the wire thicker and better for their feet than hardware cloth, but their droppings will pass through the 1/2"x1/2" too.
Some rabbits will chew on anything that they can get a hold on with their teeth.
I've made my own cages based on the cages from quality cages, KW cages, Bass, and the other bigger manufacturers. You need the heavier cage wire, good wire clippers, some sort of latch, j-clips and j-clip plyers. I've finally hit a point where I just have started to buy my cages. Some I've bought used, and others new. There is a resale market for good cages. (I've sold some too) There are different methods to drain waste without a tray, but I use trays with my cages since they are inside. In the past I've done a tractor type system where there was a raised wire floor in the cage, but no tray, and I moved it around the lawn with a shelter over it. Hard if you have a lot, but it can be done with a small herd. I mostly have guinea pigs, who are just as much of chewers, and need to be in a tray since the wire will hurt their feet.
Many larger scale breeders won't post photos of their setups online, because of threats from followers of the groups we don't discuss here, but you can get an idea from looking at some of the cage makers sites.
thanks
