Is there a set number of days before you can charge-off and account due to an overdraft? If so, how many days is it and what, if any are the notice requirments?
Also, how does 31 CFR 210.4 play into this.

Generally you should be considering a charge-off on/after 30 days. I know of no minimum time. Certainly reasons could dictate that a balance is an immediate loss and you'd be fine to charge it off right away.

As to Reg J, I can't speak on that. The charge off process is an accounting issue, not a "check collection" issue.