The downside of the matte acrylics available is a lack of pure colors. The downside of acrylics that are pure is an inconsistent finish ranging from matte to satin to gloss depending on color and brand. In the past ive used Tamiya additive or Reapers anti shine additive. Never cared for tha Tamiya but Reaper worked okay. I purchased Badger Air’s Minitaire paint line Flatitive. Big bottle that mattes better than the Reaper. You only need a very small amount say a brush full added to four brush fulls of paint. Anything more will give chalky finishes. The advantage is a little goes a long way and the eye dropper built in gives a lot of control. Its very opaque and liquid. I think my days with Dullcoat are over.