This is what I ended up building. I am going to start on a new 3U rackmount case for my gaming PC soon since the 4u workstation one I am currently in was designed 20 years ago and does not fit water cooling well.
I plan to follow up my last build with this new one once I get started.
When I built this one I just did a basic layout in Visio because I was hand cutting everything. I google the size of the motherboard I wanted, I google the size of large PCIe cards and added a bit, and just added it all up.