RE: Beveling Control Hinge Lines
What I ususally do is to lay the control surface flat and lay a straight-sided pen down next to it. This is just about perfect for a 1/4" think surface, but you may have to shim up the pen for thicker surfaces.
Now draw a line down the edge. You don't want the line perfectly centered, just close. Then flip the piece over and draw another line.
Next I just place the surface on the edge of a table, hold a sanding block at an angle and sand till I hit the top line. Flip and repeat.