Interesting There's a lot of people claiming the opposite. My own experience is that you only get a true matt coat from waterbased acrylic mattcoats. These are however not as tough as enamel gloss coats.
Generally varnishes use acrylic, Vallejo, Galleria etc, or polyurethene/enamel, Humbrol, Blackfriars etc, as the carrier. Testors uses a lacquer hence the appalling smell.
Unless you intend to bounce the figures off a wall (in which case I recommend a yachting varnish) a good quality modern acrylic is as tough as enamel and I have yet to find a matt varnish that will give as flat a finish over gloss as it does when applied on its own. All matt varnishes will lose their flatness if handled too much as the matting agenct makes it susceptible to the natural grease found on fingers.
The other reason I prefer to use acrylic matt on its own is that gloss varnish has a tendency to affect colour tone, particularly browns which go much darker. I have wondered if this is why some Foundry base colours appear to be ligher than one would expect as the Foundry style assumes a gloss followed by matt varnish.
Pat