jkm,
Preface: I am real picky about my turf. I'm the trophy lawn guy on the block.
When I traded my BX in on a
B7610 the dealer had two 7510's (same frame) on his lot. One had turfs, the other had R4's. I drove both of them back to back, doing all kinds of maneuvers and trying to see which would tear up the grass the least.
The conclusion..... Both tires did about the same amount of damage!!
Here's the deal: The only time the tractor tears up the grass is when you are turning sharp. During the turn, the outside edge of the outside front tire bites in and tears up the grass. The R4's have a "bumpy" edge, and leave stutter marks in the grass. The turf tires have a smooth edge and leave an even slice. Pick your poison.
Personally, I went with the R4's and had the dealer's promise that I could switch tires for free if I wanted to within two weeks. I kept the R4's.
In order to keep from trashing my lawn, I have stopped going around my trees in a circle at full lock. This would create a rut in no time. Rather, I make about 4 gentle turns. Kind of hard to explain, but you'll get the idea once you play around with the tractor.
On the other hand, the BX will spin around the tree a full lock and leave no scuffing at all. Something to think about if mowing is your #1 priority.
Good luck.