I saw Coryell twice.
He and The Eleventh House opened for Captain Beefheart at Town Hall, NYC, 10/28/72. A smoking show. It was really a great band; Mandel and Marcus were particularly impressive. The most perfect part of this show: no vocals! So it was The Real Great Escape material without vocals - very enjoyable. I recorded this from the seats with my little cassette recorder, and have enjoyed listening to it through the years.
This band also did a radio concert on WLIR-FM (Long Island) 5/1/73. Also very enjoyable, but, alas, there were vocals.
He did a solo concert at SUNY-Binghamton in, IIRC, spring 1975. Not so enjoyable. Like Jim said, it wasn't focused; it seemed like he played to the whoops of the crowd. I remember at one point he played slide guitar using a Coke can.