Dr. Honda you are absolutely right for the most part. Your calculations work great for small GA airplanes but for big stuff it's a little more complex than that.
I'm a Checkairman on the MD11 and also instruct at Boeing in Miami on the 737,757 & 767. Moments on all real airplanes are precisely calculated and equipment is places exactly in those locations. Every piece of equipment has a moment calculated and a % of MAC. Installation is the same on every single airplane. If it was not the weight and balance graphs would be off.
On RC planes this method cannot be done because everybody installs things in a different location even if the instructions say not to do it.
Everybody is an expert which complicates things in the RC world so things should be kept simple.
I have logged over 1500 flight on Tornados this year and I am telling you guys on our airplane 12 3/4 inches or 1.5 lb on the nose is correct for the general publics flying style and easy of handling of this airplane. Now somebody like KC which has lots of turbine experience he can move the CG to his flight style which he has done.
The empty weight of your airplane for the Version 1 or Version 2 Tornado's should be 14lb give or take 1/2 lb with a P60 or 15.5 lb give or take 1/2 lb with P70,K80
If Your plane weighs more than this you have not followed instructions and added extra things to the plane.
So I recommend you use the conversional CG method to calculate your CG. Let's keep this simple guys it's not rocket science.
Now anybody wanting to have some fun and if you are in Miami come and sign up for my advanced aircraft systems course at the Boeing training center and get some stick time on a 737-800 simulator. Lol