fabricate.... kroil oil for sure. And then weld up a spark plug base thread to an air hose chuck, that way you fill cylinder(s) with a good amount of kroil and then put maybe 30-40 psi on the cylinder for a time period. I forget how long we used to do it, maybe an hour give or take, and then try to turn it. Very many times the kroil being forced into places, will free it all up and it'll run just fine with no other work.
Have freed more than a few tractor engines like this over the yeras.
I see you are already freed though... but kroil in the ring grooves would be a really helpful thing in totally freeing them. IMHO
