Once you have the MAC for both wings and the CG balance point as a percentage of the MAC. connect the two CG positions with a line. Measure up between the wing Gap distance and place your center of lift (CL) at the 57% reference line. Project this location up and balance your biplane at this postion (see red lines). A CG forward of the CL makes the model more stable. Placing it aft of the CL makes model less stable.
I'm trying to use this method for a Bucker Jungmeister model. The gap is 12.5 in. and the top wing MAC is 9.44 in. and the bottom wing MAC is 9.9 in. Is this the best method?