I haven’t had any issues flying trips with TK instructors, they have all done very well on the line. I have flown with numerous senior pilots in both seats who obviously hadn’t read the FOM or FM in years. Who would you rather have, someone who is up to speed but doesn’t fly the line as often or the guy who is extremely complacent and just passes their sim checks with the help of gouge and the script? Providing a TK instructor has the seniority to be captain on the aircraft that they instruct, they’ll do fine in the left seat.