I own mostly NQW, buti have one California buck.
My bucks get 30x18, as do any young ones I intend to keep.
My does get a 30x30 USUALLY.
Ihave one doe in a 36x18, and another one in a 30x24, but ones with upcoming litters, get a 30x30 cages.
Now, I have raised rabbits before, but only about 6 weeks into this again, but I made all my own cages, and I like them deeper (no more than 30 inches though) than I do wider.
Example, I made a 8 foot long cage, with 4 holes in it. The two cages on the ends are for the bucks, both are 30x18 (18 wide, 30 deep) The two in the middle are 30x30 These are for expecting mothers.
on the other rack, I have tone 36x18 THis has a doe in it, but she is not pregnant Theother is a 30x18, but she is younger (5 months) Will breed her soon enough. ONce she is bred, she will move to a 30x24,.
I have a system, I breed my does about 10 days apart (that's the general plan) and they go from breeding, to a 38x18 or 30x24 When they are about 2 weeks out, one of the bigger 30x230s will open up, and I will move her to there.
Most people prefer wider holes than deeper, but I have a limitation on available space, I can go deeper but not wider, so I choose to go deep with mine, but I wont go deeper than 30, cuz its too far of a reach, even for someone 6'3
The only drawback I have is on the bucks on the 30x18 I have to putt feeders on the sides, which is why they are on the ends