How much longer is the R kickstand than the X?

Just getting ready to put R (dirt) wheels on my X. I'm going to make a shim to add to the end of the kickstand to make it as long as an R. How much to add???

Completed the swap, and while I don't have an R stand to measure, I would guess it is about 1.25" longer. The X stand still works with the R wheels, but the bike leans a lot while on the stand. If the ground were soft, I think it would easily tip. A chunk of wood, or misc rock would be enough to fix the problem, lol.