I think I'm quite late to this conversation...and I "think" you already found a combination that worked for you -- but is it 'bass feeling' that you weren't quite getting / feeling?
I've never used one, but a buttkicker might be the solution that works great for you. Downside is I think you have to have particular furniture to put them with...but people do speak highly of them. I have never felt / used one myself.
With my own experiences, I didn't feel I was getting the bass I wanted, but thought that was as good as it would get. Then having a second sub (with the two calibrated) smoothed out the curve and I've been extremely happy since. I know you said your Outlaw doesn't have calibration, but I am sure there are other solutions that might get you there as well.
Batpig pointed out (and I think it was true) that when I had my one sub, I had my receiver set (for 2ch listening) to have the L/R outputting full-range, along with the bass from the sub. Most people view that as a 'double-bass' and somewhat of a fallacy in making things sound better...and actually a problem, but batpig mentioned that it may have filled in some of the range where the low freq waves were canceling each other out.
Funny to think of bass waves visually, but it made sense on a graph...and it did sound better to me...so that might help you out a bit too, in potentially tweaking your crossover settings & any optional settings your receiver offers in that arena.