I'm re-posting my comments from another thread...
If you're at FDX it's 99.9% likely that your logbook is just a vanity exercise... do what floats your boat.
If you're someone might interview again some day, I'd only log non-seat time if you're the PIC you signed for the ship, otherwise just time in seat. That's my perspective as someone who used to hire pilots... not really happy to see people logging grey area time, that might speak to your operational philosophy or character. Prefer to see the conservative approach. There are plenty of good ways to demonstrate your initiative and can-do attitude to a potential employer, but P-51 time is not one of them.