Thank you both for the reply. So this poses a question. Level would mean the wing in a flying attitude? The Stab in a flying attitude? The fuse datum line level?
Suppose the plane has a positive incidence on the wings and you use that as reference? Is that "level'?
The same goes for the stab.. it could have a positive incidence too.
On this plane I used the Fuse top structure as level with a bubble level. To me that seemed "Level" but maybe not THE level necessary for a good CG via the Xicoy?