Yeah, the 15/6/1 is amazing. I've used it for some pretty large outdoor shows this summer and it filled the stage and got out into the audience pretty far. I've also tried my rig with two 15/6/1s, one for each pickup for my Starfire/SII. Sounded pretty amazing. I had them spread out over the stage. I'm not sure the rest of the band was all that into it.
The Bag End cab is not something I'm in a hurry about. It's been sitting in my basement for the last 15 years, so if the right drivers show up, great, if not, oh well. I think the last time I took it out to a gig was ca. 1992. It really is insanely big and heavy.