fine tuning speaker placement

Just moved to a new home with a 22Lx14Wx10H ft room and trying to fine tune the speaker placement. Room is untreated. Speakers are Avalon Diamonds.

I first use a velodyne subwoofer test tone analyzer (only up to 200Hz). I moved the speakers around as I watch the frequency graph changes. Then I position the MIC in several possible seating posistion to find a seating position. Speakers ended up at 4ft 6inches from the front wall & 3ft 4inchnes from the side. I am sitting 3 ft from the rear wall

Next, i use a PAAA3 spectral analzer to check the 20-20Khz response and ended up with >10db narrow band suckout at 3.6Khz, the rest of the spectrum is resonable flat.

My questions:
1. Is there a spectral analyzer that generates a curve repeatedly on a screen similar to the velodyne unit but do the full spectrum? I find this more convenient as I can see the chnages on a graph while moving the speakers around.

2. Is it time to play with toe in to minimize the 3.6Khz null or should I treat the room? I am new to room treatments and is GIK package 3 a good place to start?

3. My measurements correlate well with the Cara simulation on Rives audio website. According to the simulation, another good location would be putting the speakers halfway into room. This is PITA because my speaker cables are not long enough and that means moving the rack, too. I am missing some midrange clarity and soundstage depth in comparing to putting the speakers 7ft from the front wall. However, the bass is very uneven.

4. The frequency response changes tremendously with tiny variation of head position (dist to rear wall). what do u use to position the mic precisely. Would the average of two meaurements ( one for each ear) be more accurate than one measurement betw the ears?

Many thanks