Finger methods are quick, cheap & convenient. Put a piece of tape where you want the balance, and pick the plane up there with your fingertips. Add weight & repeat until balance looks right.

The CG Machine is also convenient. If the CG is 3" behind the leading edge, you set the little rulers on 3", and the vertical alignment wires let you quickly place the assembled model with the supports 3" behind the leading edge. Then you add weight until the little level bubble is in the middle, and you're done.

For swept wing models, some additional measurements may be needed. Models with more than about a 60" wingspan will be somewhat cumbersome to balance on the CG machine, and larger models will be too heavy for it. If you have one, and only do smaller models, you will be delighted with the simplicity and ease of storage.

For larger models, check out the previously mentioned Vanessa setup, for which you'll need an A-frame support, or an exposed rafter in the garge (for hanging the thing up.)

Good luck,
Dave Olson