I'm pretty close to you, Benton Harbor, and I just got my first tank up and running. While I didn't build the sump, I have some key learnings about the operation, with some things I like and don't like so far. I have a trigger 34 under a 75 gallon tank. Socks, skimmer, dual reactor, fuge, ato.
For starters I think the most important thing is flood protection and there are many aspects to that. Obvious, is the power outage when all the drain and return line water volume needs to fit in the sump. But also that last chamber of your sump, holding the return pump, all the water in that camber needs to fit in the DT should the drains or overflow become plugged.
Next for me was the sound / noise. I didn't realize how much noise difference there is between a 1/2", 1" and a 2" waterfall. I had to adjust the working levels of the various sump sections to get a quiet operation by keeping the levels closer together. Also the overflow in the DT needs the same low drop to be silent.
Next is thinking through the where all those items in the sump go and the maintenance steps, like changing filer socks, replacing media. Is there enough height in the cabinet to get the skimmer in and out its chamber? Just because it fits in a 9x12" chamber doesn't mean you can get it in and out to clean the pump. I did a bunch of trial runs before the tank was on top the stand and needed to change the orientation of the sump.
I saw your other build thread and your setup is going to be beautiful. Good luck. Let me know if I can help in any way.