My stereo micing session went very well although I used two out of the three techniques I know of, but haven’t used much.
The AB pair is a commonly used technique that I like to use on acoustic instruments. It is an easy technique to setup and works very effectively.

It worked nicely on the marimba giving the stereo image an natural pan of the rising scale of pitch. Spacings between 17 to 20 cm are detectable by the human ear, as this distance is equivalent to the distance between the two ears themselves.
The XY-Pair I have also come across on a few different occasions in the studio at home. Its a fairly simple technique to setup and gives impressive results. The most commonly used XY set-up consists of two cardioid microphones angled commonly at 90° to produce a stereo image.
I prefered the sound captured from the Euphonium benefited from this setup as it held a warming character which also emphasized the christmas ’silent night’.

The Din-Pair unfortunately my camera ran out of battery so I wasn’t able to capture a picture of my setup. It is a technique i know of but haven’t used very often. It is fairly awkward to setup but i managed eventually.
DIN stereo uses two cardioid microphones spaced 20 cm apart and angled at 90° to create a stereo image. If used at larger distances to the sound source the DIN stereo technique will loose the low frequencies.
I prefered this technique on the Euphonium again as it produced some nice characteristics to the fell of the sound. Although I prefer this track to the others, I also appreciated the sound that it also captured from the acoustic guitar.