I broke my Fiamma chocks first time out trying to increase the height! Unless they are well support along the whole length like kbsserv shows they can snap. I now use the remnants with planks and sometimes chock even higher than shown in the pic using wood off cuts.
I have three planks all of different thickness and place these where required to ensure the van is level in both directions. Usually only two are required but occasionally three.
The best journeys are not always in straight lines. To read about our travels visit >this page< Latest updates 6th March 2019