Then you'd have a much easier time using the ARC software to sort out your subs for smoothest placement response as well as speakers placement. Since you have similar software already, then play with phase,crossover etc. and save it to one of your config. settings.

From what I've come to understand the ARC, DIRAK and REW with UMIK are all similar in the way you can use the graphs to get best out come then use that tech. For R.C..

Being you already bypass the ARC setting getting into the REW maybe a waste of time except for having more precise readings of a particular bandwidth.