I don't have a solution for you to paint any acrylic by brush without leaving brush strokes. Except for detail work, I usually paint with an air brush, and even then, I don't use much in the way of acrylics.
I used a brush and acrylic paint on the seats because it was the color I wanted and had on hand, and I wanted stoke marks and unevenness. Ironic huh... - Mark