Hmmmm. I'll bet once you try the Juggernauts you'll be pretty sold on BKP. FWIW, if I had a 6 and a 7 string they'd both have Juggernauts in them. I like those pickups that much.
Aside from that, I'd be tempted to put a Holy Diver bridge and VHII neck in the other guitar, only since I like variety.
Aside from that, between Black Hawks and the Titans, it's a tough call. Mostly, I never play DiMarzios so I can't comment on them, but with the Black Hawks, Misha liked those and the aftermaths, so the Juggernauts are kind of a hybrid of the two but also sweetened and phattened.
The Black Hawks are apparently unbelievable but we're talking tonnes of clean power which is similar to actives. It's really a question of whether you are down with that or not. At any rate, as much as I love the Juggernauts, I believe variety is the spice of life so definitely try something different in the other axe.
I hope this makes sense, it feels very disorganized.