So I rough sanded the LE & TE, then started to apply the wingtips. PassTime does a very good job of providing very light 1/4 balsa stock, cut into 5 pieces for each tip. The center 2 are hollowed out. So I'm there, and say, "why don't I add some permanent weight to the left tip while it's open?"

So I did, about 1/3 ounce, plumber's putty rolled and flattened, held in place with some RTV.