I might have to get in on the Bag End action. As memory serves the old deep red cabs got along well with the GK 800RBs and their boost knobs back in the day, so I presume the coaxial speakers can handle at least a little overdrive, but will gnarlier distortion toast the high frequency compression drivers in the old deep red S15X-D cabs? I generally play with noticeable grit but occasionally go full Lemmy. I do typically run an LPF at 4–5khz anyway, if that matters.
(I did try searching for an answer and didn't find much; please feel free to point me toward any existing threads or comments on the matter, with my thanks.)