I have pretty good acoustic. My goal is recording vocals in stereo and compare them with mono takes as solo and in my mix.
I just learned from a website:
"In a nutshell, mic up the voice with 1 mic facing the singer (in cardioid) and place a 2nd mic right near the first, but in figure-8 with the diaphragms perpendicular to the source.
You can then “decode” the M/S by copying the figure-8 track to a new, 3rd track, reversing its phase, panning it hard left (or, I believe, panning it opposite the direction the “front” of the figure-8 mic is facing) and then panning the original figure-8 track hard right.
So you’ve got your mono cardioid track sitting C, and a pseudo-stereo L/R track. Adjust levels to taste. You might consider keeping the L/R tracks down during verses and bringing them up during choruses, eq’ing/comping/verbing them differently, etc. "