On my F3A planes, they are painted balsa, just one coat of light sealer and sanding, then the colour and clear cote, that's it, it has come down to that to keep weight, just make sure the balsa is sanded to a perfect finish, I use 800 grit for final sanding before paint.

The finish is simply perfect. The way you described is perfect, it is a shame Sakura did not built anymore planes, I was told what happened but don't remember....

As you said Anthony, just try it, I used a sealer from Sig, item SL-003, really good, I use Dupont Chroma System, which has a flat base coat and clear, the flat coat dries fast and you need very little paint compared to other Uretane paints, the only thing is do not apply a really loaded coat, just very light coats, even if it takes three or four, weight is minimal, but having to sand and repaint is really something I hate.

Hope it helps

regards

Alejandro