Well, I had a small 140Hz problem (dip) in my new room and I spent a lot of time to find the optimum listening spot, which happened to be a little further back than first suggested by the acoustician. The room was shortened a little in construction, which probably was the reason for this.
Now things both measure and sound good, and working is easier than ever before. I love it! My speakers are a sealed box design, which seems to make placement a little more tolerant than with other types of driver loading.
I should be getting my new Towersonic stands here within two weeks, so I'm soon able to lock the placement in for good.