Awesome! Thank you for giving me a very straightforward and concise answer. Hard to come by sometimes!
Haha thank you both
@justingraham and
@jsker! I am an engineer working on Mars rovers and i have a lot of CAD experience. Sadly, i am rather embarassed by this halfa**ed CAD i've displayed here but i'm glad you all like it! I find it really hard, and you have obviously seen it in this thread, to get technical concepts across 100% without clear diagrams.
That said, I still needed more so i printed some 1:1 and modified my design tonight. I think i'm ready to lock it in with the company! See images below!
Stress on the bulkheads were a major consideration in my designing. While yes, it isn't shown here, i worked over a few ideas and i think i am prepared for them to deliver the tank, standpipe-less and i will build the rest on my own.
I would have the same concerns as you regarding bulkhead cluster and glass, however, this tank is being built by A.G.E. and it is their style to go with 1" PVC bottom! Now, the strength is still a concern when considering torquing the bulkheads on 30" long pipes but i will be sure to secure the base of them well. I'm considering not just doing rock but also maybe taking a 12" tall, large diameter PVC pipe that will go around the PVC standpipe bottom section, then fill with mortar to stabilize the whole thing and keep them from stressing the bulkheads.
I understand your thinking here but you may not have to fill it, depending on the size pipe. My return column is hollow and without water inside of it 
It was a little bit of a trick but it worked. I used a 4" diameter pvc pipe and fit it to a pvc toilet bowl seating ring. (you can see it in the pic) It was siliconed all over the bottom so no seepage there and used a pipe cap at the top of the column with the perfect size hole cut into it for the pipe to go through and completely siliconed as well. This way if there is ever a problem I can cut the silicone away to get to the pipe and bulkhead.
@prsnlty I love what you did with your tank! Please tell me more about what DIY rock is? What exact products did you use? (please link me?) Your tank is stunning and i hope mine looks half as good as yours.
Thank you 
I love DIY Rock and here is the thread that started it for me. I believe my posts begin on page 5. https://www.reef2reef.com/threads/diy-rock-tutorial-info-thread-rocks-walls-floors-etc.31971/ and also on my build thread beginning somewhere around post 24 - 64 I think. I show how I did it and I think the recipe I use. If you should decide to try it feel free to ask questions 
If you are a hands on project kind of guy you'll love making the diy rock!
One deviation from your style it sounds like i want to make is to fill the bottom, at least half, of the rock-overflow-box with a solid of some sort such as mortar. The water doesn't need to fall all the way down there anyway (bean animal benifit) and so i don't want stagnant water down there so i'm going to reduce the depth of the box.
Commented a light weight solution above 
I've decided to lock in my design as 1" pipes. 3 drain and one, likely to be, return. I say likely because if my 3x1" drains aren't enough drainage, i can adopt the 4th as a drain and route my return line up around the side of the tank through one of the structural columns i'm going to build to hold up the ceiling.
I actually have 2 - 1" drains and 3 returns on a 180g. You need to be sure to balance the return flow with the drain flow. I have a 3/4" in the column, a 3/4" over the back and a long sand bed spray bar that sits on top (semi buried) of the sand bed running down the center of the rock ridge and caves to keep fresh water flowing throughout.
Tonight, i decided my CAD wasn't enough and i printed 1:1 drawings of my tank's standpipes. I realized the 1.5" pipes are entirely too massive for my liking. I too agree
@justingraham that 1" full siphon is around 600 to 900gph. From what i've been reading, i think this is roughly what i'm looking for. It should be adjustable to some degree with the open channel. And again, if all else fails and i need more flow/drainage, i can convert back in the 1" center "return" pipe as another 600-900gph drain and route my return up over the top.
Good idea and yes I agree with Justin too
the 1.5" pipes were insane looking, too large and came too close to the walls for my comfort. Also, the stress concerns....:
Thanks folks for getting engaged! I hope people are starting to get at least a little bit as excited as i am.
This weekend i'm hoping to get to demo'ing the wall and seeing whats underneath. Then CAD it up and start CAD building!
Stay tuned!
