New to the site snd just found your post. Did the plane fly better with the second power source?
I converted mine using an AXI 221234 and a 3 cell 1500 battery. I cut the bottom out of the nose to mount the battery against the firewall to get the CG correct. With a 3 cell 1320 battery, it was tail heavy and very sensitive to pitch control. I used a 9x6 prop and take off from grass (I removed the wheel pants as they clog easily). Plane flies great. Not 3D but very aerobatic: inverted, tumbles, spins. Fun touch and goes on windy days. In 1 year, only 1 mishap. Ripped off the LG on a very gusty day resulting in a very hard landing. A little epoxy and good as new.