RE: Dual Batterey Pack connection
The main problem with that kind of setup is you ideally need two very closely matched packs (as close together in the same batch as physically possible) to help prevent the charge/discharge problems you're talking about, it's not hyper critical though the setup you're talking about will work just fine. It's not very fault tollerant though so if that's the reason you want to switch to redundant packs you'll need a more complex setup.