Solvaset first timer?'s

use very little solution at a time. 

I would recommend doing one decal at a time. That way if your method doesn't work for the first one you can try a different approach for the rest of the decals. Apply the Solvaset sparingly and keep checking the decal every 10 min or so. reapply if needed. And some real thin decals just don't hold up to solvaset. they will stay wrinkled or silver badly. You may or may not need the setting solution first(blue micro-set). Just experiment first.

I'm an armor guy and I always use Solvaset (only), even on flat surfaces. Gives me a little reassurance that the decal will stay and not lift after it is too late I guess. Been doing this for many years...

Paint,
Gloss coat,
Decal,
Solvaset,
Gloss coat,
Weather,
Flat coat.

No problems even years later.

HTH

I use both setting solutions and decal solvent. If the decal is being applied to an easy, flat surface, I may not need the solvent. So, I always use setting solution, but wait and see after the decal is positioned and tapped down well, whether I will be needing solvent.  Usually even if I let it dry after just using the setting solution, and find it has not nestled down well enough, I can then apply the solvent.

I don't ordinarily recommend vinegar, even white, as some brands have spices or other things that can leave deposits.  Setting solution isn't that expensive.

Solvaset is the only solution I use. The product will settle down any decal on the planet. I either gloss up the area to be decaled by polishing with a soft cotton cloth or brushing Future on. If I use Future, I let it sit for at least 2 days otherwise the Solvaset will cause a haze on the uncured Future. I slide my decal in place and blot it with a paper towel. Then I brush on the Solvaset. Leave it alone cause it will wrinkle up as part of the process. If for some reason you end up with a bubble or two when it dries, use a sharp pin to puncture the bubble and dab on some Solvaset.  I do each decal as I go. Just make sure the decal is at the location you want cause once the Solvaset is on, the decal cannot be repositioned.

I have found the setting solution (vinegar) doesn't have much effect, except to make it difficult to slide decals around to position them, after you apply them.  I soak the decals in water with a tiny bit of dishwashing detergent to eliminate surface tension, so they can be easily moved around before they dry.

After I let the decals dry thoroughly, if they need to be  settled down to conform to panel lines, contours, or whatever, I will use the solvent solution, carefully and quickly brushed on, so as not to tear the decals.  It works rather quickly, so brush it on, or simply use an eyedropper, and leave it alone overnight. Also, I have found that Testor's metallizer sealer works on decals much the same way as the solvent does, but I have only used it over metallizer, so test first before you use it over some other kind of paint.