root, after doing a search in the original thread before the continuation, I found this post: "Prop spinner I flew mine with OS 46AX , battery against the fuel tank, and still had to put 2oz of weight in the nose. Just put in an older OS FS 70 Supreme it weighs just .2 of an oz more than my prev setup."

From reading this, I get the impression that you should mount the .46AX as far forward as possible and put the battery right behind the fuel tank.