I have a 6' Woods rear blade purchased from the same JD dealer as my 4115. I did order the mushroom style, bolt on, skid shoes. After mounting the skid shoes I found the skids would dig
in any unfrozen surface. I fabed a set of castered gauge wheels to follow the rear blade.
I noticed a big improvement. I now use the blade set about 3/4" higher than casters, carry the full weight of the blade with the wheels. My driveway stone stays on the drive, not scraped off to the edge. (as before.)
I would not waste the time & money on mushroom type skid shoes.
I welded a bumper mount type 2" receiver to the tail end of the large square tube of the blade pivot support. Next, I fabed the castered gauge wheels to pin into the 2" receiver. I can remove the gauge wheels from the rear blade by removing one 5/8" dia. pin.
Note: the 2" receiver works great as a optional trailer ball hitch. I love multi-tasking!!
I hope this helps. Good luck.