if you a setting up a herbie over flow the noise should be minimal with either setup, the only down fall i see with external overflows is the tank can't set flush with the wall but atleast you won't lose valume from the tank

im not too worried about the tank sitting flush againts the wall since ill need space to run wires and potentially have room in case i need to get back there. once its in place its not moving, so i may as well leave myself work room haha

i guess my next question is what size sump would be proper for a tank of that size. I've been advised to go as big as i can go, but i know theres gonna be equipment in the stand. I would also like to plan for a refugium in the middle of the sump.

i was thinking of a sump 36"w x 18"d x 15"h, with a 12" refugium section in the middle. would that be big enough? should i look at going slightly bigger?

thanks to an online fish calculator, this would give me 90gallons of show tank volume, and 42 gallons of sump/refugium.

any suggestion would be greatly appreciated