Yeah, I know I'm new too, but I'm hoping you learn that you don't paint fabric... you dye it. And I wouldn't dye an existing container unless you can COMPLETELY disassemble it to where you have nothing but fabric attached. No metal, rings, strap keepers, whatever...
Although I have no experience painting helmets I saw this G3 on Jeb Corliss's Facebook (https://www.facebook.com/photo.php?fbid=345765552133071&set=a.174465782596383.34744.171260932916868&type=3&theater), he also provides the link for the artist who did the painting, so im sure you could ask him for some professional advice.