To avoid the silvering it's necessary that decals are perfectly tight to the surfaces
When I used to be an aircraft modeller, dealing with the decals was one of the steps that i mostly hated (and this is one of the reasons why I switched to tank modelling

)
Firstable I applied a gloss coat on the model
When the gloss coat was cured I applied decals and stencils using the decal setter. I used the microscale products, nowadays it is possible to use the Gunze stuff
When the decals were in place, I softened them using the decal softener. Decals softener seamed to "melt" the decal but it was just a momentary appearance. It was important to never touch the decal during this step. When the softener was evaporated (...and if I did all in a right way) decals were perfectly tight to the model surfaces.
After the softener phase I used to apply another thin glass coat to definitely hide the film.
Finally, if it needed, I applied a matt or a satin coat.
It was boring, but unfortunately there weren't alternatives
In tank modelling decals are maybe less important, but anyaway , process is more or less the same:
1 gloss coat
2 decals with setter
3 decals softener
4 gloss coat
5 matt coat
The main difference consists in the fact that Usually tank decals are smaller than aircraft ones, so I can apply the entire process only in the areas where the decal are going to be placed
But, of course, stencils are A LOT easier to use!.
Anyway Trifon, in my opinion your model is nice indeed
You did the camo in a very convincing way in my opinion
cheers