The best one to buy is the lithium one the PX28L they are more expensive than the silver ones but last a lot longer I've had a couple of them in my Canon F1n AE and Canon A1 for at least five years and they are still ok.
Thank you for the replies. The PX28L looks like a candidate for the camera battery. The battery for the winder is a 2CR5 and I think those are common.
I sent an email to Mamiya asking them to verify that Li batteries can be used in this camera. I downloaded the manual and there was no mention of Li batteries.