I was really surprised to see the numbers all over the ballpark when the results are to be the same.The closest to the 26.85 figure is when you take 25% of the chords.The distance between the two 1/4 chords divided by 2. I get 26.2" from the FW leading edge. I believe your right about making a small scale model. I will see if he would like me to make one for him. This plane has twin motors mounted on rotating post that are on the upper sides of the fuselage. The motors will be rotated for short field take off, very short take off.
Is my thinking correct that first you find the CG per the wing layout, then you position the motors on the CG or behind it?