I appreciate all of the comments and advice in my several parallel mic threads. Basically, I am having difficulty getting good acoustic sound out of a hodgepdge of mics that are apparently not suited to acoustic guitar. While a new mic or two is definitely in the very near future, last evening, I decided to press on with what I have, to kill some time, and I managed to carve something interesting.
My EV676's were not working in any good way, but the EV664 was doing something interesting, even if incompletely. In my random attacks on the problem, I used electrical tape to close off the openings that surround the head of this mic. Then I used the tape to built up a small funnel around the screen. It is only about 1" deep, but it seemed to alter the sound in a beneficial way, by increasing the bass response, and knocking down an annoying metallic range of frequencies that I was hearing on any notes played on the B string.
Then I aimed the mic straight at the neck/body joint from a 45 degree angle, about 16" away. This produced a functional and interesting (yet entirely unlike acoustic guitar) sound. I then double tracked the part, panned, EQ'd, compressed, and levelled the parts to satisfaction. I used significant amounts of EQ on the low end, and perhaps 5dB around 2K, after coming to the realization that getting a satisfactory and listenable sound trumps maintaining microphone purity or integrity, at least at this time.