Hi Al, I don’t have very much info on the VC7…. it was a unit that I designed when I started experimenting with MS recording.
The MS system on it is simple…. the ‘M’ output is simply the sum of the 2 mic amps, the ‘S’ is mic amp one mixed with a reverse polarity output of mic amp 2. So, if you drive a cardioid mic into mic 1 and a figure-8 mic into mic 2 (with the fig-8 mic at rt angles to the cardioid one,) the MS outputs become right and left. (Read it up on the airSOUND websight.) 
You should not have any problems using the mic amps… they are transformer balanced, and very high quality.