Base salary above assumes you're type rated and not paying off the bond, expect 5k/year less otherwise.
30-50k net for SFO sounds about right, depending on the base, taxation, whether paying off the bond or not etc.
Time to upgrade depends on your hours, everything was suspended for the last 1,5 years but upgrades have already restarted, and we were told that every SFO meeting the requirements (>3500h factorised) will have a chance for upgrade before next summer season.