A lot depends on the depth of the colour on the decal or the thickness of the decal. Some may let the under laying colour filter through. Like George I would prefer to mask and paint.
OK it sat up overnight, I treated it about 4 times with solvaset. There is one area that bugs me, near the outer red cannon patch. Otherwise it is not bad, I still have another brand of setting solution I can experiment with.
Both sides done with leading edge yellow stripe. The right side came out much better, I have a very small area on the left side where there is a thin gap near the wing tip, decal didn't join up correct but still not a "fatal flaw".