I usually gloss B4 decals as well, and then a thin gloss over, then a thin satin. Satin will allow the wash to flow and also give you some tooth for other effects.

I would suggest that you experiment on a toss-away kit or a piece of plastic sheet. Just try the process on that first before a 'good' kit. You'll learn a ton and if it all goes wrong, no big deal. Keep trying on junk plastic until you get it the  way you want.