Tail Brace Wire Rigging - These tips were found in SWPC Tips and Techniques CD.

"For the tail brace wires, 12 to 15 pounds pull in the center (using a fish scale)
 should yield a 1/2 inch deflection" ..... wing brace wires 12 to 15 pounds also.
 Clyde Smith, Jr. says he likes to see the tail wires at 12 and the wings at 15.