Do you have Krylon in your country? It would produce much better results than that stuff and be more durable. Another good primer specific to modeling is Mr. Surfacer. It works really well on paper and is good for prepping the surface for paint because it doesn't obscure detail. The best part is you can brush it on and it self-levels, so you don't have to worry about brush marks on your parts. In any case, yes, weathering will remove the shiny-ness from the model if you use weathering powders. For the most part. You'll probably want to tone it down with a matte coat, though. They can't take the gloss away completely, because it will still shimmer through the "dust". Fantastic work so far, though! And I can't believe I've been following this thread the whole time and didn't realize you were building a pair of Y-wings!