A cautionary suggestion, GoGreen:
If your bank is not planning to offer to authorize ATM and/or one-time debit card transactions that would overdraw a consumer's account -- which would generally require that you assign a consumer an amount by which you'd "puff" his balance for the purposes of authorizations, an attempt to get consumers to opt-in under Regulation E is likely to be viewed as a UDAP.
You'll also need to notify those opted-in customers from the acquired bank that you won't be providing overdraft services for card transactions, thus voiding their earlier opt-ins.
If, on the other hand, you plan to add what you're calling an overdraft protection program (which I assume is an automated overdraft payment program), then your Reg E opt-in solicitation would make sense. Just be sure, if you are FDIC-supervised, that you adhere to their November 2010 Guidance on such programs.
John S. Burnett
Fighting for Compliance since 1976
Bankers' Threads User #8