Part 91 GIV payscale midwest

[johnny taliban]

got this "friend" who has an opportunity to get typed and fly a GIV for a private owner (plus some charter/about 500-550 hours a year total). The owner is gonna upgrade from his GIII to the IV. My friend is currently typed and flying as a captain on the G1159. What kind of salary can he command in a midwest city?

thanks

johnny