My memory is a bit hazy on Parsons involvement with the original quad mix, although I would not be surprised if it is truly his work in that regard. Thanks for any response on this one.
I don't know about the original stereo, but Parsons definitely did the quad mix - he wrote an in-depth article about how it was done in 1975, entitled "Four Sides Of The Moon". He also did a comparison between the quad mix and James Guthrie's 5.1 mix back when the 5.1 SACD first came out.