I had trouble keeping up with farm equipment maintence, not my favorite thing to do.  Even with another person to help, the idea of greasing 2,600 pieces of heavy equipment sounds like something I would be asked to do after I die, assuming I did not live a good life and went to the afterlife in the wrong place.

On the coupler part, 4-jaw were always better for me than 3-jaw, I looked for them often, and bought several when they were available.  Our local Rural King Farm Supply has them off and on, and Shoup had them in the catalog once, don't know about the new one.

My Lincoln electric gun had a 4-jaw when I bought it, but bought a new one this year, it came with a 3-jaw.