Sue: JGB guarantee $10,000 plus 60% gross over $25,000 (for both shows), plus lights and sound (est. $1,250). With the grosses they earned, band got an additional $7,013 on top of their $11,250.
ref: Variety, November 26, 1975, p. 44, shows $19,420 gross on $21,000 potential. While it would usually list the whole night's numbers, it seems only to report the early show in this case.