Jim, I seem to recall the EVM15 and the 3015 having pretty similar (highish) efficiency. Comparatively speaking, two 3015-loaded TL606 cabs pushed by a WA is pretty beefy-sounding. Not sure if you're considering it, but I wouldn't recommend using two TL606 cabs using those two different drivers, they sound very dissimilar from one another. I like them both, for their different strengths.
I recently heard two 3015 drivers loaded in a largish 215 cab from Rollersound and really liked the sound, less compressed than in my two TL606 type cabs, just smoother overall. No affiliation, the owner is good people:
Roller Sound Custom Guitar & Bass Cabinets