I just booked all my ADRs for August 26-September 3.
I needed a credit card for Chefs de France, Flying Fish, LeCellier and Cape May (dinner/no characters).
I have a credit/debit card that I use ONLY for my ebay and keep very little in that account since as soon as it hits my account from paypal, I take it out and put in an envelope to save for Disney. Anyway, I think there is about $20right now in that account and I was able to hold my ressies for 4 ppl for each restaurant using that card.
I am sure using a credit card will cut down on multiple bookings for one dinner.
I know I was guilty of booking mutliple ressies until I knew exactly what I wanted before my trip and canceled.