Thanks for the detailed analysis, Paul! That's pretty neat that the later style could adjust to a plow furrow.
Sounds like both you and your neighbor got a good deal. It's also nice when people remember the good deeds you've done over the years for them, and I'm sure, knowing you, you helped him out a bit over those years.
Hey, if your dear wife ever convinces you that you need to reduce the herd, let me know. Being that my bride is newly from the city, she hasn't figured out yet what is and isn't "needed" for the farm. I think that means I can add at least 4 more tractors to my flock before I risk getting into trouble. :-)