First time using this on figures,how much should I thin it when brushing it on a figure?or at all?

I noticed their Field Gray color did not look dead flat when dry?any issues with that?

They have a flattening agent X21 flattening base . You add this to the paint a little bit at a time till you get what you want it's suppose to make gloss paint flat and flat paint dead flat if that's the results you want .

dont brush it on figures use vallejo paint. unless you airbrush it...search airbrushing figures on youtube for the technique.

What David said. AS far as a flat finish, airbrush some Testor's Dullcote lacquer when you're done and get a nice, consistent flat and strong finish.