I am sure there are ways of doing it with math and levels and things as such, however the only way of making sure that it is correct is to use a meter. Maybe you could get with your local club and see if you can borrow one. I would loan you mine if you were in the area. As a side note, most all of the Great Planes kits are designed to have all the incidence built in that the plane might need so if you built it as per plans you should be close. Good Luck, Dave