Quote:

3 different thicknesses, so what determines which one to use??

thank you

I am only aware of two thicknesses. 5/16" is from the factory. 3/8" if the body is distorted to the point that 5/16 will not allow proper fitment of the trim.
Craig

2014 Ram 1500 Laramie, 73 Cuda
Previous mopars: 62 Valiant, 65 Fury III, 68 Fury III, 72 Satellite, 74 Satellite, 89 Acclaim, 98 Caravan, 2003 Durango
Only previous Non-Mopar: Schwinn Tornado