I just bought an MSR too and yes that battery positioning is very important to get right, and for me it was just a bit confusing to understand exactly the proper arrangement. I might be wrong (someone correct me if I am!) but the only/best way to insert the battery so it goes in all the way is to put it in so the battery label faces DOWN towards the ground. Trying to put it in the other way it just didn't seem to want to slide in all the way & I got nervous not wanting to force it in & break something.

It didn't seem right though because when putting it in label-side-down, the red dot is no longer visible.. no problem though just plug the connector on so its red dot was also not visible. It all works great but seemed weird to me the dots weren't on the visible side..

Anyway, slide the battery in so the thick black collar is TOUCHING the black battery holder on the heli and that should solve your balance problem.