The problem with setting up a sweep involving a savings or MM account is that transfers FROM that account are limited under Regulation D. Your customer would need to move funds from the Savings or MM account in person in order to get around those limits. And "in person" doesn't include anything except physical presence at a branch (or ATM), by courier or other agent, or by snail mail.
John S. Burnett
Fighting for Compliance since 1976
Bankers' Threads User #8