I use a bench mounted trimmer/router for my l/e on control surfaces, and use either 30, 45 or 50 degree bits depending on whats needed. My guide fence is a piece of 3/4 ply 4' long and 6" wide with a slot to clear the bit. one end is held with a bolt and the other has a slot for adjustment and is fixed with a threaded stud, wingnut and star washer on a fender washer. very quick and easy to adjust. I also has a number of different radii bits for L/E etc on tail feathers etc