I just spent another 90 minutes reviewing the mono "no-mix" one-at-a-time approach vs. stereo pre-mix, and am torn. Al's presets are the best I've ever heard for ANY drum library, as they sound very realistic and well-balanced, and probably would be OK in any song context, give or take some tweaks to the individual levels of some top kit pieces in the main drum view (vs. the mixer view).
I feel like I'm missing something by not taking advantage of his presets, so it may be time to switch to "mixing in the drum VI" and having just one stereo drum track in the host DAW. Certainly this saves time, and with his excellent yet subtle settings, the kit seems glued together and manageable, as the miking is so good that one doesn't really need post-processing.
Al's subtle application of room reverb to the top snare and the overhead pair is just enough, along with light Fairchild 678 compression/limiting on the output buss. I could also defeat that last stage and use my own 678 plug-ins without losing any of the stereo image or balance of Al's presets.
One of the things I am noticing with this kit, due to the excellent room miking, is that tracking each kit piece as a mono-summed independent track, is losing the movement within the overall space. With past libraries, I haven't felt anything was lost, when I compare results (vs. miking an actual kit and mixing it the traditional way), but it always nagged at me as the main potential drawback with my longstanding approach.
So I think now we have a library that is so perfectly miked and thought out, that it is "safe" to bounce just a single stereo combined track that is already balanced and minimally processed.
I do not know if the EZX Big Band library has the same mix settings as the SDX Decades library. The other, Toontrack presets, are too extreme for my tastes, as usual, but all of Al's hit the mark. Up until now, only a few presets have done that for me, and my recollection is that they were some of the artist presets for the new stock SD3's kits.
EDIT: After another half hour of mix comparisons, I have concluded that the built-in reverb is crucial, as it's the only place to properly add that light touch on the top snare and the OH mics, unless every single Toontrack channel is sent to its own DAW track (vs. each kit piece's combined signal). I ended up preferring the 670 not being on the internal mix buss though; I'll use my high-end processing plug-ins on the stereo drum bounce from Toontrack, in the DAW instead.