Wow. Just went through the thread. I’ve never been a fan of bow front/curved tanks but you might be changing my mind
A couple random things that I’ve no idea if you’ve addressed already.
Sand sifting fish - I had a sleeper gold head goby in my 210. That guy did an amazing job of keeping my sandbed clean, only problem was that the bottom 2-3” of everything was always covered in sand lol.
Tank placement - it’s possible to move the tank a few inches... it’s a gigantic pain in the bottom bit but doable. I had this same issue with the 210 and it was a big enough problem that I ended up moving it. The way we did it was “borrow” 5 large trash cans from Home Depot.. wash them out and drain all but 2” of water from the tank. Then have a few people lift up the stand about 1mm and move it forward about a half an inch. Repeat the process on each side until the tank is off the wall. Then pump the water from the trash cans back into the tank. Only things are.. my tank was sitting on a very very overbuilt diy stand. Made it a lot easier to handle after I took all the side panels off. And I had flexible tubing on all the plumbing with quite a bit of slack so it didn’t affect the plumbing at all. Not sure if this is something that would work for you but thought it would be worth sharing. (Also, one of my friends that was helping is a structural engineer and spent about a week telling me of all the risks to the structure of the tank with doing something like this. It’s not a great idea. But in dire situations...)
And as far as lights.. what about adding another 52hd to each mounting arm? Have two of them on each side, would certainly open up more options for coral placement.