Yeah U joints easy as and agree about yokes 20x harder. Not much comprehensive info around about what is happening in the yokes when greasing them. I gather the reason is like you mentioned 'you can over grease them'. Also figured the force from driving would just push the extra grease out anyway. I had a fair few big flicks of grease on some tubing and stuff when I looked underneath after driving. Will take a clean rag and some waax&grease or acetone to it 2moz.The joints I pumped until I saw fresh bright red grease. Those slip yokes though were worrying me. It's not hard to get to them. Front is harder, but would only take 15 minutes to get back under there. I thought I had read somewhere that you could over grease those yokes. That's what was in the back of my mind. Maybe someone else will chime in too.
I think its a dirty job more than anything ! wasted so much good grease on the front yoke ! went all over the place lol