In case you can't read the photo above:
The stripes were five alternating black and white stripes. On single-engined aircraft each stripe was to be 18 inches (46 cm) wide, placed 6 inches (15 cm) inboard of theroundels on the wings and 18 inches (46 cm) forward of the leading edge of the tailplane on the fuselage. National markings and serial number were not to be obliterated.
The TF Giant P-47 based on wing span is a 1/5.09 scale airplane. 18 inch stripes should be 3.53 inches wide. If you want to just round to 1/5 scale then 3.6 inches wide. 3.6 inches inboard of the end of the star and bar on the wing and 3.6 inches in front of the horizontal tail.