Hay Mark, been there and done that. Built one as A club trainer, three of us learned to fly on that plane. What A kick in the wind, you can get them to fly backwards.
Mode, in most cases I can mount the RX above any of the other parts or all the way back. In this case the battery had to be mounted aft of the wing right at the former before the fuse aft section started.
I also have A race plane built for A friend with the battery all the way back in the fuse just in front of the stab. Reason: A 3 pound plane fully loaded until the engine, muffler, spinner and prop were installed then it hit 4.5 pounds. It's still A little too nose heavy. As someone posted, this plane isn't built to crash, just go real fast and turn left.