Tire Selection Trade R4's for R1's? JD 3320

[lipchili]

I recently acquired a 2009 John Deere 3320 with R4 tires. I'd like to switch to an R1 tire, but from what I understand it is expensive to buy new as you must change the rims also due to different sizes, keep the 4WD in proper timing, etc.

I've seen where some guys have swapped tires with others. Anyone out there that has R1's on a similar model looking for R4's? These R4 tires have 350 hours on them.