My tandem axle 11400 lb 5th wheel RV trailers tires have 1 1/4" and 1 1/2" between them. I do my tug test with them between the tires. My adjustable chocks once tight will not allow the tires to roll even in 4 low. The tires just slide.
My adjustable chocks are just part of a system I use that stabilizes the trailers movement so the trailer has no motion which due to my medical condition is a requirement for me.
We camp on dry and wet ground.....asphalt....concrete....gravel surfaces. Some times we may have to use 6"-8"+ of wood ramps to level the unit side to side. Wood/rubber/plastic chocks won't work in these conditions as we found out the hard way. Finally adjustable chocks hit the market and eliminated constant chock adjustments.