I know a couple of career instructors (ie. not hour builders) who fly solo from the right seat, purely because they're so used to it. I fly a fair bit with other members of my group so am reasonably happy in either seat, although it makes sense to place yourself in front of the panel with most of the instruments on it.
As far as logging goes, if I've flown someone else's aircraft with them logging P1, sure, I'll put it in my logbook, but just leave the time logged column empty and put N/A or PAX as my capacity on the flight.
PS. Did one of these flights include a rather scruffy landing by the P1 at Leeds?
