I was at both of those concerts. Mingus at SMU - We were probably two out of maybe a total of twenty people there in the whole auditorium, which probably seated at least 2,000. I remember Mingus stopping in mid-tune and walking off stage. Dizzy - I remember him playing Olinga. Roker, Ben Brown, and Al Gafa, IIRC. My first concert was a triple bill at Memorial Auditorium, Dallas, 1972: Mahavishnu Orchestra, Dr. John, Allman Brothers Band.