Personally, if it were my setup? I would concentrate on several things...
Return pump baffle, how long will you be away? Do you have a reliable ATO? Thats the size you need.
Inlet side, can be tiny. Big enough for a skimmer pump (if needed), reactor pumps (again, if needed). Thats all it needs to be.
The skimmer section? Eliminate it. It can sit on the sand, or if need be, a section that fits just its foot print.
Refugium is whats left over. The bigger the better.
In my opinion, the easiest, simplest solution, is going to be the most reliable.