MicroSet is diluted acetic acid (vinegar). It has a softening affect on some decals. I've used it to lay down decals on, but if I'm not precise or quick, the decal can set too soon and be damaged when I try to re-position it.
I have gone back to using water for position, then wick it away and use Set to snug the decal down.
MicroSol is isopropyl alcohol i believe (not sure of the diluted strength) and has more of a softening/dissolving affect on decals. If Set isn't getting the job done, try Sol.
Paul