I am a believer in, but not a user of the plumb bob method. Vic's drawings show the model suspended by a four-point harness (the lines going up to the dowels) hanging from a two-point anchor (the dowels), which hangs by one point (from the pulley or skyhook).

My understanding of how the plumb bob method should be used is to suspend the model by two points, one forward and one aft of the likely cg. This could be accomplished by slipping a noose around the tail, and closing the noose not tight but close around the after end; then slipping another noose around the nose of the airframe and closing it. Now the model hangs by two-points, and is free to drop the heavy wingtip as well as settle with the front-to-back cg under the plumb bob.

My method, which works best when building a plane, but which can be retro-fitted to an ARF or a built plane acquired second-hand, is to hang from a one point suspension, that being a hard-point dowel glued into a vertical-grained balsa block, epoxied to a convenient point directly over (or under, in the case of a low-wing model) the recommended or intended CG. The dowel is pre-drilled with a pilot hole to receive a small screw-eye or screw-hook, which can be removed when the balancing is complete.

Using the one-point method allows me to put the framed up model together, hang from the ceiling, then place servos, batteries, other parts here and there until the plane is hanging perfectly level--front to back, and side to side. I can then install all these accessories in their approximate locations with full confidence that the finished and covered/painted model will be pretty close to the intended cg. I can then rehang from my screw-eye and place let's say the battery to balance almost to perfection, even correcting some side-to-side balance if necessary by putting the battery up against the light side of the fuselage--or screwing/epoxying a small piece of lead somewhere along the wing spar.

The point to all this is not that I have put the model together with a perfect CG, because what is "perfect" is a matter of pilot judgment and preference, which can only be determined by flying. The point is that I can easily set up my components, then eventually take off and trim-fly a new model knowing that the CG is in a safe and flyable range.

If later on I make changes or repairs which throw the cg off, I just turn the screw-eye in again, do another CG check, then remove the screw-eye.