Model Master makes a brush on clear matte labeled "Acryl." It is not as flat as Testors Dullcoate (which I use), but does a good job for the most part. I use it as a wash, actually. I mix in some flat black and paint it on -- no mixing up a new batch of wash each time. I take a paint brush and keep adding black to the clear flat bottle until it gives the result I want.
Nice figures, by the way! I don't notice any glossy sheen in the pics!