Over the years I have dipped many Mustangs, 1960's SL's,
67-69 Firebirds and last month dipped one 69 GTO and Sand blasted the other. The GTO cost under $1500 to dip.
I have never seen or had a creeping problem.
I wash them with soap and water than give the body a good blow job than DA with 80 and wash with wax and grease remover and spray epoxy.
Too me its the most perfect way to do a car.