I'm thinking of redeeming some of my airline miles for Amex gift cards to help pay for our vacation at CSS 12/25-1/8. I've already booked the dates and was wondering if anyone knew if I could call and make several $100 payments with the Amex gift cards, as that's the denomination they'll be in. I did a search and found that you can call and make a payment any time, but I'd like to know if there are specific gift card rules. Thanks!