I could have sworn I had a decal tutorial. Getting to the chase of that tutorial that is pertinent:
Decal systems come with setting solutions (all designed to break the water tension and allow the decals to easily move to where you want them before blotting and having the adhesive contact the model surface).
The 'Sol' parts are solvents and each is designed for specific types of decals but no one tells you! MicroScale/SuperScale have a line of decals with super thin film. Decals solvents were too hot so they made their own. Other companies using MicroScale/SuperScale rebranded the product (such as Aeromaster). I keep these for thin decals. Also, I start with them on decals I never experienced before. The frugal way is to use vinegar. Have you ever noticed the smell that MicroSol/SuperSol has?
Many of the Japanese kit decals (which were not sent out to Cartograf, Fantasy print, et cetera) are thick and the MicroSol/SuperSol solution simply tickles them. This is why Tamiya and Gunze decal solvent solutions are much hotter. Yet, I never bought them as I have hotter!
I bought a set from DaCo Productions and Walther's SolvaSet. The latter supposedly does both in one shot. However, it is very hot, not as hot as DaCo Decal Solution. Neither have a 'Set' solution as they literally soften the decal to the point it melts the film. Great! Unless you have one of the thin film decals.
As Paul found out, the best is to experiment finding the right ratio of heat for the decal setting solution being used.
Regards,