Dynamic Volume is used when watching sources that may have unpredictable and changing volume level usually TV programs. It can also be beneficial if watching movies at night and you don't want the LFE to be that pronounced. Activating Dynamic Volume eliminates the the impact of LFE especially in heavy explosions and gun fights but still provide pronounced center channel volume level
Activating the Dynamic Volume during normal listening makes you lose the details of the explosions and other scenes heavy with LFE.
Setting your subwoofer gain at 9 o clock before calibration is a very good starting point. Desired result of the sub level calibration is between -3 db and +3db. If you get anywhere near this, then that should be good enough, however, if you really want to have it within parameters, yoo can make adjustments, if the sub level calibration is too low say -6 tp -12db, decrease the gain setting and recalibrate, if its too high say +6 to +12db, increase the gain of the sub then recalibrate. Please take note that the resulting levels is reckoned at Reference Level, meaning listening at 0db or in your case at 82 db. If your not happy with the results, it becomes PREFERENCE thus defeat the purpose of the cailbration.
What Audyssey recommends after calibration is to set all cross over setting for the speakers to 80 hz while the LPF of the LFE to 120 hz speaker distance must be kept as is though as this is not a measure of the physical distance but a measure of the time delay or how the sound should arrive at your ears at your listening position. Changing this may result to inaccurate sound levels or a particular channel overpowering the other.
If the resulting level calibration is way too low, you may adjust each channel by 3db, my listening voulme is normally around 66db and my speaker calibration levels are set to around -3db for the fronts, -4.5db for the center and -5db for the srurround
for a better LFE, i set my sub level calibration 6db higher than the result i get after calibration meaning if i get -6db after calibration, I manually set it to 0db.