I don't think there is a per say best way but there is a best way for each builder. This a couple choices I have used and still using just depends on what mood and what weight balsa I'm using.
Thin Super Glue: absorbs well, dries fast, makes a good hard suface, but I can't stand the smell.
Waterproof Wood glue: No oder, easy brush on, absorbs well, makes a good hard surface, I use 2 coats then dry overnight.
Counter top epoxy (Lowes): My current method. Thin, absorbs well, cures hard, needs at least a full day cure time.
This is my current method for my wood cranks.
1. After sanding I put it on it holder (i use the nail and clothes pin) I use the table top epoxy, brus it on just what the wood can absorb and let it sit over night to cure. No rotation.
2. Sand if any lose grain pops up.
3. I apply one more coat to give me a good surface the paint and I use a turner for this step and let it turn and cure overnight.
Hope this helped more than it confused you.