Most minimums are driven by insurance requirements. My company requires 2500TT/1000PIC/1000ME for SIC contract pilots. The Chief pilot has 5500TT, and I have 4200TT.
Most corporate operators also require that their FOs have type ratings for insurance purposes. All of the newer citiations require two pilots except for the CJ1/CJ2. You can get a single pilot waiver though by taking a checkride in the actual plane for all of the the CE-500 line (V, Ultra, Encore, Bravo)