How can I minimize brush marks in polyurethane where wood grain meets from different directions?
I would sand the surface with a fine grit paper to remove any brush marks. Wipe it down with denatured alcohol to remove the dust. Get you a foam roller and roll a coat onto the surface. Roll slowly to prevent too many air bubbles. Allow it to dry and put a second finish coat on it. Three coats is standard in the industry. Foam rollers tend to leave a smooth finish overall with no worry of brush marks. You can also add some Japanese Drier to the poly to make it dry faster.