I wouldn't have a cage (for any livestock) more than 36" deep. It's hard to reach back that far. Mine are in what used to be rabbit cages that are 24"x36"x18". One is a three-level and the other is a long cage with 7 compartments. They don't seem to be bothered by the height.
The floor is 1/2"x1" welded wire mesh. Get galvanized AFTER weld, preferably 12 or 14 gauge. If you get before weld, you'll have a rusty mess within a year or two. You probably won't find that wire in a hardware store. Most of what I see at Menards/Home Depot/Lowes is 16 or 18 gauge galvanized before weld. Hardware cloth (typically 20 or 22 gauge), IMO, simply isn't sturdy enough in the long-term. Smaller wire more prone to rust means a higher likelihood for breakage and unexpected repairs down the line.
But, if all you can get is something from a hardware store, it will probably be OK for quail with diligent maintenance. Rustoleum is bird safe, so if it starts to rust you can scrub it down and coat it with Stop-Rust. It just needs to cure outside for 5 to 7 days. I used about 8 cans on my stacked cage, although that was extremely rusty when I purchased it.
Many people I've spoken to have said to get doors that flip inward, so the birds can't wiggle their way out. We have doors that flip out or up, so we solved the wiggle problem with pieces of cut cast-iron pipe to add weight.
I'm not terribly familiar with the climate in Louisiana. Are you prone to frequent freezes? (We can't use PVC up in these parts because the sub-zero winter will make it too brittle.) If not, you might want to look into the PVC hanging cages for rabbits. They're inexpensive and easy to build, and could be adapted with some basic math to accommodate quail. They also give a nice "plug and play" frame to swap out damaged cages without disassembling the whole shebang.
Like James, I'm using newspaper (shredded here). I toss everything from the dropping pans into my worm bin. Eventually, some gets dumped in the garden, and the chickens work through the compost and eat the worms. At least, that's how it worked when I had rabbits. Hopefully it will also work with the quail.
