white hex head self tapping screws. Found Them

Paint does not really adhere all that well to stainless steel.

I'd certainly wipe the screw heads with a solvent before hand.
Appliance epoxy has good adhesion and durability in my experience.

I aim for a lot higher than 'just fine', which in my book means that it has not failed yet.

My new batteries are charged using 13.6v absorption voltage for a 15 minute duration. It works 'just fine'

Good luck with that.