The only way of getting the sub to match in timing with the speakers is to physically move the subwoofer around, but the location of the sub in phase may not be the best location of the subwoofer. And vice versa.
Ideally you want the subwoofer in the best location, then adjust phase to blend it in, then perform a combined ~40hz-300hz correction, only cutting the peaks, not boosting. Working out where to start correction is more tricky as you need measurement equipment.,
Would be good idea to use REW/UMIK to determine subwoofer response, speaker response, how moving the sub interacts with the overall response, then working out where to perfom correction.
One you don't want to do is boost 20hz-30hz, as neither your sub or speakers can reproduce those frequencies, so you'll be driving them way past the limits.
The Wiim measurement EQ process will show you some info, but you'll have to do a few runs, take screenshots. It's like like REW you can do a dozen or so responses, and compare measurements.
If the Wiim had RTA, you could have the subwoofer on a dolly, move it around the room and wherever the summed response is flattest that is the best location, at least with the limitation of the rel not having phase.
I believe Anthem ARC in their products do have a RTA function, quick measure where it sends a sustained noise
