Apologies for what may be a simple question. Local chandler has 10 amp
regulators for only $10 more than the 6amp model. 10 amp is way above
my needs but other than $10 is there any downside to using the higher
rated regulator?

And while I'm at it what's the best practice for joining the solar wire
to the battery post. I.e are there connectors to join to the existing
large connector?

Thanks