OK, I see ur point.... I dont have any pastels, but do have colored pencils... Can I use the same theory and try to use that???
As for the Matte coat, I do that after I have the decal down with a slight gloss to seal em??? So, decals down, gloss over them, hit it with the matte coat, followed by some panel line work/weathering, then another matte coat to finish it all up???
Pencil might work? will have to experiment myself to see if this is satisfactory....
Finish ALL decals on the first gloss coat, when they are all on and settled in, then you gloss over the decals to have the same overall gloss finish to your model....then you finish with a matt coat or two....bit more weathering work then you may seal this if you desire....I would allow at least a day between jobs...Decals, Gloss, Matt coat then we see what is required....ok?
I'm off to bed now talk to you tomorrow...