I used 2 mixing sticks and taped it to the elevator closest to the rudder. I got it to mix really close. it's down to a millimeter or so on both up and down. one other flying guy said " did you balance it side to side". Ah, no. He picked up the plane from the tip of the spinner and near the center of the back of the plane and the plane plopped to the right. same side that drops in the loop. he looked inside the plane and noticed everything is down mid line except for my throttle which is on the right. Since I have an OS FS91 mounted horizontally (rockers on the right) - he said maybe that is why the plane could be favoring to drop the right wing. he suggests to mount the battery on the left wall of the plane and what ever I can move to the left. I was thinking maybe put weights into the aluminum wing tubes on the left. what do you think about that?

My battery is well secured under the tank. I have the tank pushed far back - right infront of the wing tube. Nothing inside moves except for the servo connectors to the wings - they are slightly free hanging inside.

I flew thru the loop a little faster and noticed that right wing drop tendancy slightly went away. I maybe just exiting the loop too slow and stalling that heavy side.