I have always liked Tester's Dullcoat, but sometimes it dries to a semi-matte rather than a dead flat finish. I recently read on-line another modeler say that he lets a bottle of Tester's Dullcoat sit until the "flattening agent" (you know what I mean, all that 'stuff' that gathers at the bottom of the bottle) settles to the bottom. Then he draws/pours off a quantity of the solvent. This increases the concentration of the flattening agent and depending on how much you draw off, the finish that can vary all the way up to dead flat. I decided to give this a try. I took a new bottle of Dullcoat which had settled completely and poured off about 1/3 to 1/2 of the carrier/solvent. I was a bit afraid that it might be spotty or have flecks of flattening agent in the finish so I tested it on a scrap piece of plastic with a flat paint on one side and a high gloss black on the other. i thinned the Dullcoat as normal for my airbrush and gave each finish a coat. The matte finish was still matte, no surprise. But the high gloss dried to a DEAD FLAT and there was no flaking or spotting on either finish. I then tried it on my current project that had gloss and matte surfaces plus decals and I got an even dead flat finish over all. 60 some odd years of modeling and I am still learning.