Thinking about all of this I have a few remaining questions,
1) I have read that it is not a good idea to have any of your three outside dimensions of your cabinet being equal. I am not sure this is really a problem if bracing actually breaks up the size of the panel. In addition, a typical square box using butt joints will have two panels of lesser width anyway. Thus it is really the size of the panels with determine the resonance not the actually outside dimension of the box? Am I thinking correctly here?
2) Should braces be staggered at odd intervals inside the box? Are standing waves really an issue in a small box?
3) If bracing moves the resonance outside of the subwoofers passband, that seems good, but will that present a problem higher up with what the mains are producing?