I use Solvaset exclusively over Future and never experienced any problems with it attacking paint through the Future. What type of paints do you use (I use enamels exclusively).
I always apply the decal into position first using water to wet the location first, then move the decal into position, adjust as necessary, then use the edge of a paper towel or a q-tip to wick away the extra water. This insures that the decal has minimal-to-none air underneath it. For larger decals I will also gently press it with the papertowel/q-tip to insure it's got good adhesion to the surface. Only then do I apply the Solvaset. On really complex surfaces the occasional air bubble will occur, under those conditions I will apply a spot of Solvaset and then gently "work" the bubble to lay down using either a brush, a toothpick end, brush handle, etc. depending on the size/nature of what I'm dealing with. Very rarely will I need to *** a bubble to get it to go away. HTH!