Rushing always makes for an accident waiting to happen. Have you ever noticed that? This is when the machine acts up or you suddenly realize that the long piece of material you bought for the backing has a "marriage" in it that you didn't see when you bought the fabric.
My opinion would be to take a picture of it and let them know that they can expect their quilt after they come back from their honeymoon. They certainly won't be needing it before then and this will give you the space and breathing room you need to do a good job on it. No fuss, no muss. I can understand wanting to give it to them at the wedding, but we need to remember that we need to be kind to ourselves and not stress ourselves more than we have to.