Once again this subjet about upgrades has been treated in different thread .
As Wilma said it depends on the type you join .
you join on large cabin you seat locked for 2 years at least
you join on small medium upgrade depends on avalibility and your capacity to go through the course.
Mike is telling you 250 hours in less than six months, well ! once again depends the type you fly. it can take up to 8 months with no leave to get to 250 hours .
Join Netjets for the type of ops and life style not for the quick upgrade could be disappointing