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The question of what sheen level to pursue is up to the individual owner. Most enthusiasts prefer the highest degree of sheen . . . but when Plasticoat is added there will be some reduction in the level of sheen.
When I had the Ruths at P & S Trailer Service polish and recoat my '64 Overlander, I specifically asked for original sheen. For me, it allowed me to relive the days when I went on my first camping trip with my coach's original owners in 1964
. The Plasticoat has held up well and will soon be 10 years old. There is some degradation of the coat on the front and rear domes where the sun and towing have taken their toll . . . will probably be going back to the Ruth's for a partial recoat in a couple of years.
Good luck with your investigation!