Tinker,
If it were me, and I had an old tractor, and I didn't want to spend a ton of money, I would measure my existing cylinders (bore, stroke, lenght, pin size) take a good look at the vave and then go here
http://www.surpluscenter.com/
I bet with a whisker of tinker you could replace your stuff (you have to take it off to rebuild anyway) have a little fun and save yourself some cash in the process. Hell, why you are at it, spend your savings and add an extra valve and some more cyliders for a grapple
For me, surplus center is a little tough on the shipping, but for you it might not be so bad. You have enough need you might even warrant a little road trip, maybe visit a friend along the way(or have it shipped to him instead)