Very glad I found your thread and videos! Found it when researching 72x36 peninsula tanks. I am trying to plan my next upgrade and make it my "long term" tank. 10+ years if we decide not to move.
Anyway, I know it is early on but do you regret not going 24" tall? I have a standard 120 right now and absolutely hate the 24" top to bottom. With the canopy I am running it makes accessing the back corners impossible. BUT I do enjoy the extra swim room and growth for the corals even though I am 100% LPS. My peninsula would be 90% LPS and only a few very select SPS pieces.
So I was really set on 20" height but now I am wondering if 24" will be better since there will be no canopy and three sides of the tank will be fully accessible. At only 36" wide, the farthest I am reaching into the tank is 18"...just some thoughts and hoping you can shed some opinion but more importantly experience.