The shim F-705L called out on Drawing 20 is made from 0.063 stock and is 1/2 wide. I don't have any 1/2 wide 0.063 stock. Is this ripped from wider stock?
You should have in your fuselage inventory (2) two pieces AS3-063x1/2x18 of stock. Im building a 7 but should be the same. Page 4 of your fuselage inventory near the bottom of page.
All the best.