No, you are not clogging the thread, that's one reason it's here.
You definitely want to charge both packs individually regardless,, with 2 separate chargers.
For one, it's ''a' lot'' easier on the chargers,, & will make them last longer.
A lot of the packs will come with chargers anyways.
If you go with the 1109 motor, the O.D. is a wee bit larger than the 1020, which means that if you configure the motor & controller in the stock housing like I did on mine,, you will have to grind more than I did off of the controller fins ect., & try & keep a bit of clearance between the motor & controller.
I would also go with the 10 - 65 gearing,, as that is a great all around efficient set up.
I have an extra like new ''dressed'' 65t sprocket, if interested, just send me a PM.
Definitely don't want a larger back sprocket than that, with the larger motor, as it will try to do wheelies every time you take off.