I never use decal solvent or solvaset unless I really need to. Decal setting solution and decal solvents are two different things. Try using the setting solution first. If you cannot get it to adhere and nestle down properly with that, only then go to solvent.
However, I sometimes get water marks even with setting solution. I suspect my bench is not always clean enough. However, I find those watermarks can be removed by water with just a touch of detergent (a very small drop). I have had good luck too with 70% isopropyl with no damage to enamel or decals. Have not tried it on acrylics, though.