Other than thinning(which I should), I also have been using the same type of brush. The results do look good, but once color is applied, I am trying to avoid the streaks. For some stupid reason I want to do this one in all dope.

I have found that over Solartex, it takes about four coats of nitrate for a good seal. I do this whether I plan to spray latex or brush thinned butyrate dope as a finish coat. If using thin butyrate, I usually find with most colors that three coats of color will do it. The secret to a really good dope finish at this point is to polish the finish (wait at LEAST 10 days) with an automotive rubbing compound. I have used Dupont #7 I believe, and also use some old cans of Sig rubbing compound, which I believe are the identical product in the smaller, Sig can. This levels it all out, and will also remove any blush that may have formed when the dope dried. This is followed by a good paste automotive wax, such as Meguiar's. Shines like a new Mercedes!

When using the dope brush, you have to work pretty fast, also, and dip in paint very often to keep brush really wet. Overlap the strokes. I usually use a 2 inch brush for the nitrate clear. Works faster, and flows the work better, as the nitrate really wants to dry fast.

I tend to over brush which is my downfall, it pulls up the bottom coats and blends the clear with the color. Getting better though, my last wing I painted with clear in 10 minutes with a 1" brush.