It should fly within those two ranges.

However always err on the side of safety, so move the C.G. forward as much as possible.

An easy way to do it, which is easily reversible, is to affix the battery pack directly to the engine mount, with servo tape and strong wire ties.

Fly the plane this way and see how you like it, then slowly move things back.

You could move the pack to the firewall next, or behind it, then close to the center of the top wing in the fuse, etc.