Hi!
What I do with Decals, part one. I handle them carefully, cut them at their very edges, soak them till they start to curl, Apply them to my clear coated surface then take a swab with distilled water on it and rub the decal gently from the center to the outside edges. Then I apply Micro-Set and after a wee bit of Drying the decal and apply Micro-Sol. ON the Decal, Never on the outside, because when you maneuver the swab from the middle to the outside the decal glue is left in a non-discernable line will clean up with distilled water.
Think about this (Micro-Set), Solvent to soften the decal and let IT conform to the surface. (Micro-Sol), sets the decal to the position and detail it covers. It's like a Kicker for the remaining Glue on the decal. Foreign bits then come loose leaving the decal looking like it was painted on. then just a Mist coat over the decal. Polish and done! NOTE:
When handling Decals,Wet or Dry, use a pair of tweezers used by Philatalists(Stamp Collectors).