Hey A8,
So, I am finding results similar to yours, although I take them as nuances of the pedal and no real problem for me:
1) Do you notice that the Octave & Clean are very loud, and the Synth voices are quieter - I suppose the peaks are loud, but the overall sound is quiet.
Yep, both have more headroom than the synth voices, but I twiddle knobs to taste.
2) The volume envelope is very dynamic, playing quiet results in really quiet & playing hard results in high peaks. I was really hoping this wasn't the case, but is what I hear. The freqbox is like this too... do you also find this?
Yes, I find that it is very responsive to your playing. I prefer when effects are responsive to more aggressive playing, but that's me.
3) tracking... the notes don't always sustain, and the octave voice jumps up to normal - pitch is correct, just not fully sustaining as long as I play.
I've heard some notes warble, but I expect this from an analog octave/synth. I'm only using active basses with my SubT.