The V40SE will handle 100db speakers with no problem. My only concern would be the impedance dips below 4 ohms. The Octave will do 2 ohms but at that point you are pushing the integrated to the max.
As far as the volume taper, I find my Ei KT90 type 2 output tubes have the shallowest but at the same time are one of the more powerful tubes I have.
As far as the volume taper, I find my Ei KT90 type 2 output tubes have the shallowest but at the same time are one of the more powerful tubes I have.