The X chocks are good at keeping fore and aft movement to a minimum. I have however run across a few issues that others may want to know about.
If using the Equalizer brand WDH, remove the spring arms BEFORE installing X-chocks. When trying to lift tongue with jack to install or remove spring arms the wheels locked against each other torques the frame which causes the spring arms to remain tight against L brackets which keeps you from easily removing or installing spring bars without a BUNCH of effort.
The other item is a theory so far but, the pad on the X chocks pressing against the tread of the tire, in the same spot for many days at a time possibly, I worry about the possibility of damaging the steel belts and/or seperating tread from inner carcass? On a flat surface I do not tighten them very much but when it is in front of our house (on a pretty good grade) when we are loading or unloading it I have to tighten up a bit more.
Just something I think about......