I sweated this step too. But I followed the instructions to the letter, tape and pencil marks, set it up on a level floor and make measurements and it came out perfect. I double checked every thing with my Robart incidence meter and it looked good but I think the measuring was more accurate. After covering I used the incidence meter to tweak wing twist.

You're getting close. You'll have a ball with that plane! I burned a half a gallon of fuel in mine this weekend. Today I was practicing knife edge to knife edge snap rolls and inverted stall turns. Sweet!

Dave