Good question, Erik!
One thing that made setting up a pair of subs much easier for me was to put a 2’x4’ x 6" Owens Corning 703 fiberglass panel in each front corner. I plan to add a second pair in the rear wall corners.
I also have successfully used an Anti-Mode DSPeaker to help with room correction. Ultimately it was a matter of trial and error and making sure I didn't become obsessive.