I always get the $5 Amazon cards individually and add them to my amazon account. It doesn't know where the number came from so you could add a husband and wife's winnings together. I think there may be a limit as to how many redemptions/month (as I recall 3 for the Amazon cards) so you may want to do it both today and tomorrow.
Thanks for the info. There apparently is a limit of 2 redemptions per day, which I found when I tried to redeem 3 cards today as you suggested. I will have more to say about the possible limit of 3 cards per month in a couple of days.