A bit more progress to report...
I've got most of my plumbing parts now and I began connecting it all. This pic shows the 4 1" returns into the tank. These will tee to 1.5" flex pvc that will snake behind the tank to the pump. The 90s are slipped on right now because there isn't enough clearance to rotate them all the way around and I don't want to commit at this point. I may use some 45s for the middle two returns to get some flow between my planned rock islands/piles.
These next two pics show the two tanks I tried my hand at building. I picked up 3/8" glass and went to town and I'm really happy with the result. I water tested successfully and then added the first baffle. I may not add anymore actually. Will do a wet run and see how the bubbles are. Space was at a premium so I don't have a large return area so more baffles might actually increase noise. I'll see...
The tall tank is basically an extra 20 gallons of system volume I will have in circulation. To do a water change I'll shut it's feed valve, flip a switch to run a little eheim that always sits in it...draining it into the basement drain (via the safety drain in the bottom of my stand). Then I'll turn a valve on my mixing tank hidden in my office (other side of the wall, in a cabinet) to top up the tank and open it's feed valve back up to bring it 'online'.
Once my flex pvc arrives and the baffle cures I'll get these into the stand and hook it all up! Really excited to be able to fire my Dart up. My fuge will be a 15 gallon tank on a shelf inside the stand but I likely won't build it. Just need to plumb everything to make sure a stock 15 (24x12x12) will fit. Cheaper than custom and I'm nearly out of black silicone anyways.