miner, note how much bigger the rear disc blade is on our old plows than the rear disc blade on the single disc plow. (it's worn down)You may get the plow to follow the tractor with adjustment, but you really need to get the rear disc blade in good order, so your adjustments will count.
after you use the plow you may want to replace the rear disc blade.
all we did was buy plow coulter blades, 18" dia,
set the old blade on top of the new blade, centered, mark and blow out the required holes with a torch.
had the new blades replaced in a short while, guess you could drill them out, but its hard steel.
Again, good luck and great find,