With all aircraft, if there is a bunch of structure over the wing and nothing under the wing, hang it inverted and look for the CG This way you won't be dealing with a CG over the point of Center of suspension, makes it easier. Also, the ability of the plumb bob to point directly at the CG makes this method easier than having it point on the fuse where you have to assume and guess where the spot on the wing is.

I'm assuming with this though that you are using a CG sling which is a simple enough device to make. It consists of two large loops of heavy cord or light rope hung from a central point, I have a screw going into an exposed rafter. These loops go over the wing of the aircraft OR the back of the wing and around the spinner held in place with the prop on some aircraft. On the same point that you hung the loops of rope, hang a plumb bob. Nothing fancy, a pencil stub, a nut anything with a little weight to it, or an honest to good ness plumb bob, you decide. Now, the airplane itself has been turned into a plumb bob and it points the way for a line from the hook towards the center of the earth just like the the plumb bob is doing. Therefore, the plumb bob is pointing at the center of gravity of your airplane. You can balance your aircraft in 2 axis's with this method, flip it sideways and catch the 3rd and no EXACTLY where that point is on your airplane.

That being said, if you have a Heavy aircraft, close to or over the AMA waiver weight, it might behoove you to get 3 of those digital scales and just do a weight and balance calculation on your airplane. It isn't that hard, but takes more typing and off topic babble than we should do in this thread.