I would use the mirror trick to determine if there is a problem and exactly where it is.
Perhaps you could just sit back a bit when critical listening or some other position change. How about a more radical height change, build a platform over the meter bridge and the the Recoils.
Comb Filtering is evil
Do the mirror bit extensively. I am sure you know this stuff already, but I will trot it out anyway for browsers. Place a small flat mirror on your console. Sit in your mix spot. If you can see the tweeter, Houston we have a problem. Try sitting back, tweeter gone? workable perhaps. Move around a bit to cover all of your sweet spot. Move the mirror around also.
Some ideas.
Recoil Stab, sure, or there are thicker alternatives.
Speaker Stand on rubber wheels? Move them as needed. Towersonic have nice ones.
Then getting crazy, hang them from the ceiling? Chains I suppose and a heavy platform, plus a layer of foam, neoprene or the Recoils.
DD