Dirac suggests 9 positions and I believe the first (central/preferred) position is the one that determines trim and delay. Ideally, you should be well out of the way, if not out of the room. 
Mic vertical with the 90 degree config file. I've never used the sock.
With regard to your attached measurement, I am not familiar with Dirac but, if it is possible, I would drop the whole suggested curve by 5db.
That reduces the size of the null corrections (best to avoid large RC volume boosts) at the expense of generating more peak corrections (acceptable). You may find this produces a correction closer to the suggested curve.
Ultimately, the final arbiter is how it sounds post RC and NOT how smooth the curve is.
Mic vertical with the 90 degree config file. I've never used the sock.
With regard to your attached measurement, I am not familiar with Dirac but, if it is possible, I would drop the whole suggested curve by 5db.
That reduces the size of the null corrections (best to avoid large RC volume boosts) at the expense of generating more peak corrections (acceptable). You may find this produces a correction closer to the suggested curve.
Ultimately, the final arbiter is how it sounds post RC and NOT how smooth the curve is.
