Not AO, but a guy out of Miami that's been building tanks for 40 years.
External along the entire back, like jnarowes, with 4 x 1 1/2" drains. No closed loop. I was going to go that route, but decided not to. Modded mj's or vortechs. Working on the KISS principal and trying to make this as uncomplicated as possible
I'm waiting on the parts for the mj's to see how they do on my 120.
I've asked the builder to send me photos of the building process. Once I get those, I'll start a new thread of the whole process.
BTW, love your tag line! Not particularly a gun guy, but I so enjoy ticking off libs. Got my Club G'itmo shirt on as we speak!