There's quite a difference between checking someone in the LHS & letting them off solo there! Co pilots in the C17 & A400M today qualify in both seats as handling & non-handling pilot (not in the C130J or Voyager though) but I don't think you'd find an authoriser prepared to send them off on their own with another co! They were clearly much less restrictive days.
Incidentally, how did you feel about going off with 2 co-pilots in the driving seats? I'm guessing that at your age then you saw no problem with it?
Congratulations on achieving your 7 decades milestone.