Wouldn't a properly setup WD hitch keep the Caddy on the level? I hate to say it but I think InlandAndy said something about coil-overs, air shocks, air springs and ther like contributing to instability and loss of control? I know my old man used to run air shocks on all his Cadillacs but he never pulled a travel trailer with it. I also remember that even with the skirts off the rear tires ran pretty tight inside the fenderwells, snow chains were impossible to use. If I remember correctly Chevy trucks use the same bolt pattern as the old Cadillacs, not sure on the offset but I do remember the old man running the Chevy truck wheels occasionally, he would pull the mud grips off the pickup and run them as needed.
Chas