I don't know why JohnK knows so much about the MCACC (which he doesn't own AFAIK), but here are some additional comments:
1) If the VTF-2 is like my VTF-3, the level knob at 9 o'clock will likely give you a MCACC sub level of +/- 3dB.
2) It doesn't matter as long as it is within +/- 10dB (maximum adjustment by MCACC). However, it seems that the auto-power-on detection circuit on the Hsu subs is located upstream of the level knob. So, if your VTF-2 seems to have difficulty "waking up" in quiet passages, you may want to set the level knob further down (e.g. 8 o'clock) and let MCACC set the sub level higher.
3) The calibration session is in fact fairly noise resistant (programmed very redundantly). Unless somebody in house is making a constant and/or repetitive noise, it should be okay. Just try to be quiet.
Everything is MUCH easier than you initially think (if you are like me). Just try to place the mic as close as your head position at the primary listening seat.
