Those are quite nice especially with the built in 1" spacer which is what I was looking to do once my bumper+winch is on. King hydrop bumps wont allow you to run spacers. Look to only be for the fronts. Wonder if they'll ever design rear ones. I'll try shooting them a message...
I could be wrong but I remember the King bump stop towers has spacing already corrected so don’t need spacer. It is made for their own bump stop after all and not to retrofit a different one.
If you are going to spend the money for a hydro bump stop then you might want to check out king’s full solution first before trying a piece meal solution because if anything isn’t right then let the finger pointing begin!