Orange guy here. i have played a Dual Dark 100 in person. Ch A is a little more vintage in your words. Ch B is very modern compressed. it was very nice but it only has a sweep tone knob which i was not a huge fan of. it got great tone really quickly an easily. i am an Orange Rockerverb MK2 100...
I haven't had the opportunity to play one yet but I expect really good results, it is one of the new Mike Fortin designed amps after all. if you don't know Mike Fortin, he is amazing. I have some decent gear and I can't afford his amps haha
no direct experience with any of it but i play my Orange Rockerverb MK2 100 through a Marshall MF280B 4x12 cab or my Egnater Tourmaster 2x12 vented cab at bedroom volumes all the time. no issues with gain at low volume at all. my Marshall TSL100 w/ out the VPR is actually better at bedroom...