Since you are building the tank yourself, an interesting thought would be to build the refugium in the display area. I had thought of doing that in my 180G, where I would have built a refugium 'wall' on the inside of the display area, towards the backside. The wall would have been made from live rock rubble, superglued together. It would have to be placed to one side or other of the tank for accessibility, but it would be interesting as the bugs would be able to enter the main display with ease.

That might be a bit too experimental though... I will probably try it out in the future some time.