Have a few questions regarding logging SIC domestic only with no type rating (C550 and LJ45)



From what I understand, domestic does not require type rating for SIC, and can be logged as long as the PIC does NOT possess a single pilot waiver? Got a couple of trips done, but I don't want to put something in my logbook that should not be there.


Also, how does high alt and high perf endorsement factor in here?


Ratings held CPL ME and IR.


Thanks for any help