There's a set of iMatch bushing required for most, if not all implements to increase the standard pin sizes. Any JD dealer will have them and I find them at a lot of hardware stores as well.
Agreed, if you have not reversed your tires, then you should. That extra inch on each side really makes a difference in stability and you get more clearance for the 3PH. If you have a directional tires like the R4 then you want to move the left to the right and the right to left without turning the tire (i.e. remove it, roll it backwards and then roll it to the other side of the tractor without flipping it). The only down side is the valve stems will be inboard.I had the same concern with my new 2520. I snugged up the turnbuckles which helped a lot. Reversing the rear tires was the best fix though ..... and it looks pretty cool as well. You might want to consider trying that if you have not already.
Even if the check chains where attached to a 1" thick steel beam, turning with any implement in the ground is not a good idea!especially if one were to try and turn with the implement in the ground.