For me Aerogloss sealer works the best. I have tried the balsa filler and the results were not as good as the sealer. I don't have a reason for this, but that has been by experience. I like the sealer because it is real easy to sand. I apply one coat and sand the fuzzies off. Then I apply 3 coats with no sanding in between 15 min apart. I then sand smooth and repeat the 3 coat process one more time. I then spray a coat of primer. After sanding the coat of primer there is no more grain showing. I normally do all this in one day. This has worked great for me, you can look at my post and see my rockets and fins. Once again I don't know why I don't have good luck with the balsa filler.