ORIGINAL: splais
In the long axis there is a bit of flex in the balsa. But what I am doing is a test as much as anything else. I let the balsa float on the legs. It is only glued on the end pieces. We will see how it goes on it's first flight.
I would not worry much about the finish at this point. If the balsa is properly glued on the top and on the bottom only it will most likely snap when the LG flexes... If you grease in your landings it might not...
If it holds, then think of the finishing. I would use Balsarite applied with an old credit card, then sand and paint.
You are doing the right thing, learning by testing things...
Gerry