So I got the chance to hang out at my practice space and mess with my amps, as well as my friend who has the amazing amp collection amps.
First, ORMAT preamp pushing 100 watt tube Carvin into Dually + Ampeg preamp pusing 3800 watt SS carvin into 66 works exactly how I wanted it to. Big huge lows from the 66, crunchy grindy nastiness from the dually. So, great success on all that.
ORMAT/100 watt carvin/Dually was as loud if not louder than Blackline SVT into a 4x10. Both amps had the volume at 3:00. So while I'm not 100% sure, I think the Dually had a lot to do with that test. That being said SVT at the same volume into a full 8x10 sounded much better/fuller/louder than 1/2 of the cab.
Dunwich + 2 Carvin power amps + 66 and Dually
VS
2 8x10's with Aguilar DB750 into 1 half of cab 1, Blackline SVT into other half of Cab 1, Hiwatt 400 into cab 2.
Overall volume wise, the 8x10's and 3 amps pushed more air than my setup. However my setup could produce bigger/deeper low end. While playing both Rigs simultaiously (via 2 seperate basses) you could still clearly hear what each rig was playing.
So not too surprising that the 2 8x10's pushed more air, since there were 16 - 10" speakers going. As opposed to my 4x15's and 2x6's, there really was far more speaker coverage.
That being said, my bass rig filled the room in a much more encompasing way (I was knocking **** off the walls) whereas the 2, 8x10 rig was more directional, much louder when standing directly in front of it. Where my rig was deep and present throughout the room.
Really the only clear victory from the showdown is that my rig was much more managable to move/transport/carry.
They both definitely have their merits. In the end I'm still super happy with my Rig, I'd take it over a couple of 8x10's any day.