Jim wrote:

I still will not however act as a safety pilot for him during IFR work
because I am not endorsed to act as PIC of a tailwheel aircraft.

You only have to be rated in category and class to be a safety pilot. The safety
pilot is not acting PIC.

George Patterson
Great discoveries are not announced with "Eureka!". What's usually said is
"Hummmmm... That's interesting...."