Got a chance to use the BBHS mirror diagonal last night and with a bit of wind, the transparency was very good. In use with the Denks I definitely observed a notable reduction in CA (relative to the prism) on brighter star's and in mono what CA I'd noted with the prism was completely gone. Perhaps it was the new gear bias but I had one of more memorable views of M42 with a Morpheus 4.5mm and even managed to resolve some stars in NGC 2158 which is a first in a 4" scope (which of course I'll attribute to the new diagonal!). Looking forward to some planet's reaching a more palatable elevation so I can put it's through it's paces on lower contrast features.
As an aside, the 14mm Morpheus might well be the best eyepieces I've ever used in a binoviewer, very comfortable and easy to see the full FOV.
Thanks Adam