Thanks Jim, I've been thinking about this.
I tried the setup in several places, one was in my great room, which is huge with a tile floor. There would be long reflections and perhaps close floor reflection but no close side reflections. Today I was in the studio, put the setup about 5 feet high, carpet floor, but rotated 90 degrees from my previous setups. I sat on a stool rather than a chair so I gained about 24" of height for the source, and it was incredible, just what I've been trying to do.
I'm wondering if it wasn't reflections off the floor and the source was too low?
I have had the guitar at least 4-5 feet from the mics to avoid proximity effect, as well as setting the mid mic a notch towards omni (or in full omni).
I'm going to do some more experimentation and see what I can learn from this.
Thanks to all of you who responded.