Wow post pictures when you get started.. be neat to see from start tofinish.
The heigth of that will require i believe 1/2" or even greater since your such a LONG tank glass.. when I was doing researhc after youy go a certain height u need the thicker glass. Also I would put some kind of middle cross beam inthe tank..maybe 2(or 3).. liek on a 55.... Acrylic might be aoption. When you call your glass company be prepared to be called lunitic LOL
If your buidling it you can make it reef ready wher the overflow is in the tank.. and then just have a return hose coming up to the main tank.. here you can house LR
and etc to add to ure bio filter..
Sand or CC its your choice in this situation IMO
since ure not doing a reef... but if you can get a sump full of LS LR
it be a big bonus.
Fish will be a limition.. Sure you have a massive length but some of the fish coudlnt' even turn around :-/. I think you have a real idea here and if executed right shoul dmake a gorgeous tank...
but a Sump is Almost a MUST in this case IMO
so you can get htat aded LR
etc without obstructing your fishies swimming room.
Just my opinions.. GOOD luck get pics