Not sure how big I can go with refuge?

[fishy7]

I have a cube tank 48"X48" and a refugium that is 45" long.
This refugium is falling apart after 6 months and I'm going to order a new one from a different source.
My question is how big can I go? I set the stand around the refugium then set the tank. I'm sure I will have to break this one out.
I have 36"X36" access doors oppsite each.
I was going to do a cardboard cutout, but kind of hard to work with the other in place.
Any suggestions on how to figure this out without removing the tank?

 

[sly]

I think others will join me in being a little confused as to what you are trying to do... Are you wanting to build a stand for your fuge and tank together? Access doors to what?...