My OEM chains were a bit too short for me. They would bind on tight turns. I used plastic chain to mock up a new set at the length I wanted using "add a links" as the temp connection point. To gauge the right length I set my truck and trailer up in a pretty tight turn and measured from there. I cut the old ones off the frame and welded on the new set.
2016 Ford F250 Supercab - 6.2 - Equalizer 12K WD Hitch
2016 Ford F150 Scab - 3.5 Ecoboost HD Tow - Roadmaster Active Suspension - (Reluctantly sold and deeply missed)
2016 Jayco 28BHBE - Progressive Industries EMS-HW30C