12hrs a day?!
That's completely nuts - even with the mustangs lack of speed that's not a consistantly achieveable figure to achieve. 1.2hrs perhaps?
I'm with Phil in that besides a new aircraft (and even then it's not like there aren't enough young CJ's on the market in Europe) I really can't see any advantage to the mustang. And his own fleet is run off it's feet - can't get a CJ for love nor money out of Bristol ;-).