I printed water slide with standard ink jet printer.. the clear didnt affect the ink at all even with using All purpose thinners to thin back.
problem with vinyl based decals is that the clear affects the glue and so you can get a rippling along the edges of the decal.
Your sprayer needs to do a fine mist coat first and then apply the finish.Issue here is that most dont want to do this as its 2 applications and so just go straight in with a heavy coat.
even acrylic crystal clear from a can affects the glue on decals.
KBS Diamond coat is guaranteed not to react with any other paint.. which it doesnt. havent used it on a  vinyl application yet though.. maybe i should experiment and find out?