pornuccio - hi.
XY configuration: two cardioid mics, capsules touching (one above the other), angled apart symmetrically at, say, 90 degrees. You point the imaginary axis through the middle of the mics at the sound source. Nice stereo imaging, used for loads of classical recording, among other things.
ORTF: the mics are touching again, but this time the grilles are spaced apart a few inches (the mics describe an X shape), and they're angled apart at 110 degrees. Also used for loads of classical recording.
So, two mics for everything. And I'd second virtual.ray's suggestion to go live to two tracks. Keep the synergy, and just keep doing it till you get it right.
A couple guys doing classical guitar won Acoustic Guitar's Homegrown CD Award a couple months ago, and they used a bedroom with an unusual shape and a carpet on the floor as a recording space. I don't think any of that's particularly necessary, least of all the bedroom.

They put one great mic on each guitar (unlike XY and ORTF), about 3 or 4 feet away. In the mix, they panned each source about 70/30. I went to their website, and listened to some free samples, and the sound's good. (Odeum Guitar Duo, if you're interested - "Concert Hall Classics".
Whether you use a standard ORTF or XY configuration, or a set-up like Odeum did, you'll get some spill or bleed on each mic from the other guitar, and the effect is very nice.
Something I'd try, if I had the mics and another guitarist to work with, is stereo mics on each guitar, much closer up.
In other words, experiment with rooms and rugs and mics and positions and distances, and you'll probably find all the luck you need.