DiMarzio's website describes X2N EQ as "BASS 7.5 LOW MID 8.0 HIGH MID 7.5 TREBLE 2.5", probably a little simplistic but consistent with what you say there. Blaze is shown as having a big bass push (which is how it sounds to me, BASS 9.5 LOW MID 4.5 HIGH MID 4.0 TREBLE 4.5). But thikning an overdrive might tighten this up. The D Activator is described as "BASS 5.0 LOW MID 5.5 HIGH MID 6.0 TREBLE 4.0" which would make it the most balanced of them. D Activator X isn't available for 7 string.
Leaning towards D Activator now (mostly because of concerns about routing the X2N). In this clip (Mike Stamper)
https://www.youtube.com/watch?v=Ev9GOrbXky0 it sounds pretty tight (e.g. no woofing on the 3:30 riff). Sounds a bit fizzy next to the blackout but thats tameable, the mids on this would come through nicely if the treble were rolled off on the amp. The blackouts have quite a lot of color, to me they felt a lot like having a boost pedal inside the pickup (that, for better or worse, you cannot turn off. At least with the FF modern you can "turn it off" by using the less aggressive second voice)
I think first I'm going to get an overdrive, then maybe get D Activators. Thanks.