Hi !
I don't know...
My father build it as on the drawing and as the cutted parts for wings and fuse, horizontal stabilizer as on the drawings by construction, no measurements, CoG at the designated place, go to the field and tow it : it was perfect.
That's all...
Well, maybe few clicks of trim, but no more...
Just fly it, trim it, and if you have lots of trim then correct stabilizer incidence... It's a Ka8b, not a formula one...