The way I saw it was that an SIC could be used in lieu of an autopilot. So I logged SIC on legs with passengers on board. On pt 91 repo legs that I was PF, I logged PIC.

Regardless of how to log the time, it was one of the best learning experiences I've had so far in my four years of flying. Once I reach ATP mins, that accrued experience is what's going to count the most.