The rears I just cut 1 groove per lug. I started in a little bit from the very corner thinking it would keep the lug stronger on the edge, but I think i'd cut it all the way to the edge if I did it again.
The fronts I cut at roughly 45* angles and cut each lug twice making like 3 sections. That was a HUGE improvement, because the R4 has absolutely NO side traction at all. They are like slicks. After cutting them, it does more work in 2wd than it ever could before in 4x4. The slipping and sliding like a fool is done, and its not an embarrassment to drive in snow in front of people now. The main thing is the wheel hop associated with spinning them in 4x4 is reduce now because they rarely have to spin unless the snow is really deep.
Before I cut them on my 2520, I hooked it to my dads Polaris Sportman 700 ATV and we had a tug of war on my snow cover gravel driveway. That Sportsman weighed maybe 800ish lbs, and I had over 1,000 lbs in my ballast box alone and in 4x4 he drug me around with ease. After I cut them we tried it again on the snow covered driveway and when he staying in 4x4, I could drag in around in 2wd like he wasn't even back there. So, it made one **** of an improvement.
I just traded my 2520 for a 2720, so I need to cut these new tires. I had it out today and it really Pi$$ed me off in the snow, so I put it away before I got too mad. used my ATV for the jobs and never looked back.
).