OK, time to finally close out this thread. The wheels are now at position #4 from the manual (gaining approximately 5" of width overall) and each rear tire has 50 gallons of Rimguard plus 5 gallons of MultiSeal Hydro 1500. I put the Multiseal HD 2500 in the front tires myself a few days before it went in. After being returned to me, I retorqued all wheel bolts (they were fine), marked the bolts. with a Sharpie and then jacked up the rear of the tractor to check the air pressure at 12 O'clock with tires off the ground, Both were a bit overinflated (25 psi), so I brought them down to 21 psi using an air/water pressure gauge. The beet juice is a little nasty to clean off but overall the prolonged experience seemed worth it!
Brush hogged a bunch of multiflora rose patches yesterday to make more food plots for this year and things went very well - I could definitely feel the difference in stability and am (so far) quite happy with the result.
Thanks for the suggestions and insights...