What’s the best way to go about mounting the battery and what’s the best mounting distance and angle for the bindings?
For the bindings about 45 degrees is good. I’d say go for a couple rides without and see where the dirt marks from your shoes are and put them there.
For the battery, velcro is great but potentially not enough if you really thrash it. It’s a cheap non-invasive way to mount it. worst comes to worst you remove the velcro and drill it to the deck.