[TimNielsen]

Also, the general rule for MS is never let your 'side' mic signals go hotter than your 'mid' mic signal, or you start introducing out of phase material. Not a bad idea the first few times you experiment with MS to have a phase meter running (ProTools Surround Meter has one) and watch what happens.

But MS is a great tool. Not sure what you'll find not having matched mics, it will still certainly work. Now the other thing is that on a figure 8, you want the zero degree 'lobe' pointing to the left, and 180 facing the right. If somehow you had that backwards when recording, you might find your left and right signals reversed. No huge deal, you would then just swap phase on the original figure 8 track and not on the duplicated, and it should correct it.

If using a plugin, remember that it will assume the mid mic is on the track left, and side mic is on the right. Usually if you watch your meters playing, before decoding you'll notice the mid signal meter will be much hotter (makes sense, it was directly facing the source) and side will be lower. After MS decoding, your left and right should be fairly balanced (assuming of course that the source was balanced, not right or left heavy). If you see something different, you might not be doing something right.

Tim