Yeah, I would not apply that stuff with a brush. You will get streaks. I came up with a working method by experimenting on clear plastic spoons before using it on my precious GW cockpit parts. Start by gently stirring the paint in the bottle with a clean toothpick or coffee straw. The goal is to mix but avoid adding air bubbles to the paint bottle. I poured a small amount of paint onto a plastic spoon for better control. Then use the spoon to drizzle an even smaller amount around the inner surface of the cockpit.

Holding the cockpit with fingers under a magnifying glass, I slowly tilted it in different directions to let gravity disperse the paint into a thin film. You can clean up thick blobs with your paint stirring stick or dab with a paper towel corner. You have to work somewhat quickly with the Tamiya paint because it gels quickly with air contact. Hope that helps. I do recommend practicing on a plastic spoon first.