Ok to the OP Turkey Herder,
I need a more descriptive post other than plugging up with root balls.
Are the roots piling up on the shanks and plugging up the plow. If so, make sure your coulters are set properly and cut the sod in front of the shank with the cut being just left of the leading edge of the shank.
or
is the sod just coming up so large that it won't pass under the frame of the plow. Don't plow so deep and that brings the question of, how big is your plow 12, 14, 16 inches?
And finally, what are the plants that created the root balls. Perhaps I don't understand what you mean. By root ball are you saying just a mass of roots that collects as you plow and creates a ball of roots on the plow or do you mean a root ball like the root ball of a tree?
And just FYI, I've had both of my plows plug but it can be lessened with proper setup.
"He has a 35 HP HST tractor, probably with R4's, pulling a unknow vintage, not sure if it's adjusted correctly plow"
That's why I mentioned "proper setup"
The reason I wouldn't disk before plowing is number one, it will lessen your traction and number two, disking was always for after plowing when I lived on the farm. Things could be different now.

Just my $.03 (adjusted for inflation)