For my system I do use 4 JL-F-113 subs. My room size is 17’ x 25’.
The subs have a calibration mic that I use to set up each separately in the chosen location.
After all are calibrated, I use 45hz as the crossover point. Everything blends beautifully and extended.
Though each sub has a delay feature I don’t use it. Try to not make this too complicated.
ozzy