Whether you preorder (I highly recommend) or order at the kiosk you're gonna have to make the decision about dessert before you start eating anything.
Its a QS location so you're not going to have a server asking if you want to dessert.
But its a bit different in that you can't just walk back up to the counter and order more.
I've never seen a to go container there but I'm sure you could bring in a container if you really don't think you're going to finish dessert.
BTw preorder can be done up to 30 days prior to the ADR.