I wanted to make sure the flaps and ailerons would have matching bend radii at the trailing edge. Here I'm checking the aileron skin with a 3/16 inch dowel. It looks a little too small.

...but the 1/4 inch dowel looks a little too big. Hrmmmm...

This is the flap skin with a 1/4 inch dowel. That's about perfect.

And now the flap with a 3/16 dowel. This is a little too small. What I decided to do is use the 3/16 dowel for bending the aileron trailing edges. I found using a piece of scrap that when bent around a 3/16 dowel, the springback causes the bend to be about 1/4 inch. I may do the same for the flaps, but they don't need much bending. Gonna have to think about what to do for the flaps a bit more.