LOL Gray Beard! I have that problem myself!
The question you asked, though, probably does bear some discussion.
it's worth noting...the Vanessa does NOT tell you where the CG
should be. That information is up to the modeler to determine, by any one of the numerous methods available. (Manual, experience, forumlas, whatever)
What the machine does tell you is where the CG
is. Rotate the dowel to bring the aircraft level (again...knowing where the datum line is is the modeler's responsibility, though NEARLY every airplane has a 0 degree incidence surface SOMEwhere *heh*), and when the plumb bob stops moving, it IS pointing at the CG.
Another recent thread on this topic brought up a GREAT modification that I've made to my own...forgive me, i do not remember who the user was that came up with it.
He used a laser pointer instead of a plumb bob...nice red dot right on the CG. It's a FANTASTIC upgrade. I'm currently working on trying to come up with a method that will lock the "laser pointer" in place, relative to the airplane's yaw axis, so i can substitute a laser LEVEL, and project a line across the entire wingspan.