Flight Safety.
I believe each aircraft is budgeted for a couple thousand hours per year, and as a pilot, last year I flew 490 hours. Training, which included going through GV initial, totaled about 30 days. Recurrents are usually 4 or 5 days each, once per year on each aircraft, plus travel.
Scheduling, you will find, is the biggest headache you will have. By dual qualifing everyone, you will never have a shortage of pilots when a GV or B757 trip suddenly appears. Grab two pilots and go, so to speak.
As far as the GV issues, Gulfstream is working on fixes and it's the GVsp. The engine issue is with all aircraft models with BR710 engines. Gulfstream just told me last week that the engine issue will be fixed soon and a program is underway to replace the fans.
Why are you looking at the 757? Have you looked into, say 2 BBJ's that could take the place of a GV and 757? (I might know of two coming up for sale soon)
[This message has been edited by fokkerjet (edited 21 June 2001).]