I was actually just out in my shop thinking on this. I've got a laser level that projects a horizontal line...I'm thinking I can work out a way to use that, then have a line right through the CG all the way across the wings. I'll let ya know how it works out.

That's what the dowel is for. Rotate it whichever way necessary to bring the nose or tail up, and bring the airplane level. The laser pointer/plumb bob is only pointing at the CG if the airplane is sitting level. (Back to our discussion earlier of how to know)

On the aircraft pictured, looks like you could set a very small/light "string level" (Any hardware store should have one) right on the foredeck in front of the canopy. Being so light and so close to the CG, it probably wouldn't impact the balance enough to matter. If you DID want to get crazy precise with it, you could certainly weigh the string level, and then offset it using the W*A=M formula talked about above.