Decided to rack it now. Didn't bother making holes to screw it in, it's not like it's really going anywhere, it's sitting on the L rails. So this is officially done and operational.
Now I can passively start looking for more GPUs if by chance I run across a good deal. But think I'm going to wait it out and see what happens. The shortage has to end at some point, hopefully.

Fits like a glove
The back is kinda bad as I originally was going to just have 3 fan holes but it was easier to mount the PSUs and motherboard facing back. Next custom case I will design it differently and more open. Probably do a motherboard tray that slides out, and the back cover will just be part of that assembly.
Overall quite happy how it turned out though. I will work on a fan controller for the front fans that can work via case ambient temperature, then swap those out for the more powerful ones. I also need to figure out how to get the card fans to run at 100%. According to my UPS I'm drawing 400w between that machine and my workstation, as they are both on same UPS so not too bad. I will need to get a bigger UPS when I start adding more cards.