Time to upgrade depend on which fleet you are and the demand.
Upgrade will be quicker on the hawker 800 fleet as we are receiving a bunch of them next year.
I would say between 6 month to one year, this all also depend on your performance during F/O line training.
As a reminder, the pass rate for the upgrade at this time is between 60 to 70% %. pass rate has been decreasing the last few months. Failure is bigger within the ex-GA and ex-military pilots communities. So read your book well in advance and take an active part on the decision making process already now.