If you're not into the "one grease to rule them all" approach you can use two types of grease and follow Kubota's owner's manual and use moly-lithium (dark grey) on the loader and polyurea (green) on the tractor. This is my approach and it works for me.That's what I figured. I keep seeing people saying...oh no you MUST use moly grease on the loader pins otherwise you'll destroy it! But you can't use that stuff for the wheel bearings and such.
As @D2Cat says, regular greasing is important regardless of whether you use polyurea or moly-lithium on the loader.