The only folks truley happy with R-4 tires are those who use them for the "industrial" usage for which they were designed. Almost any CUT operator would be better served off the lawn with R1's or on it with turfs. R4's do a sloppy job in both places but are bit better than R1's on the lawn and better than turfs, off of it. It sounds to me like turfs and a set of chains would be the best choice for your application.
I looking at a Kubota B2920 that comes standard with R4's to get turf tires cost is approx 200.00 more. 60% will be used to mow 3 acrea country yard with remaining 40% for snow blowing long driveway, misc loader work and a few gardens tilled in spring. Concerned if the R4's on this unit would be hard on the yard in the spring mowing when ground is softer from rains ect... Any real world use recommondations would be helpful.
All R1's are not created equal, nor are all R3's or R4's; Joe