Although I am not a pro , veteran modeler like others who use this forum ( ive been in the hobby for abt are year) i have found a way to make thick decal that do not sink over panel lines to still look decent. If after using copious amounts of sol and set and the decal still does not soften and drape over the panel lines, one way to solve this problem is to carefully cut the decal with a scalpel along the panel lines and fill the cuts with matching paint. Then it is just a matter of adding a gloss coat after drying and adding the finishing touches.
Just a case of serendipity....