[DocG]

Also essential is to spend the time to find the best spot for that one good mic.

As others have pointed out, moving the mic even an inch can make a big difference. A good starting point is to position the mic at the 14th fret and tilt it toward the body. Move it in various directions an inch at a time and record a few seconds of some standard passage. Label each test by saying something like "Audiio Technica XYZ100 at the middle of the upper treble bout, four inches from the guitar top, facing the end of the fingerboard" so when you listen back to compare them you'll know which is which.