The safe harbor for waiting to solicit a customer after notifying of the opt out options is 30 days. The reg, however, speaks to a an allowance for a shorter time period in certain circumstances, but it doesn't give any specific timeframes. Is anyone using a lesser timeframe? Should we strictly stick to the 30 days?

Does anyone know of any guidance out there that might give us more insight into this?

I would think that it would depend on your delivery method of the opt-out to the customer. If you are doing it through mail or e-mail, I don't think you have much of an argument to shorten the period. If the opt-out option was given in person, you might want to give them an opportunity to opt-in rather than pushing the 30-day opt-out window.