Ok Chuck: Not having the calculator program available, I found that Squardron 495 had published their way of finding the CG location.
I am not sure just how large this model is, or its weight, but will give you what I learned from 495. Finished repair, and rebuilding a damaged trainer, I hung the model in a large doorway from the engine cs, vertical stab/ top rudder hinge, and leveled it along the longitudenal axis. Hung a plumb bob from the same hanger above the model, and lowered it until it reached the fuse. Where it pointed
was the CG location. This location proved out correctly as the model was very well balanced during its flying life before my bad landing.

Just finished a 1994 Royal Aire 40T ARF purchased use, and never flown. The instruction manual gave a 4 inch dimension from the leading wing edge for the CG location which mathematically came out at over 38% of MAC. The above method corrected the location to 28% MAC. The plane flys well at this CG location.

Cheers!!!

Rich