First - check and see what state they are in. If they re already sprouted, then I'd plant them. If you use plastic pots, they won't go dry in four days, but maybe skip the heat mat. Mine have been bagged up in damp soil for a couple of weeks now and haven't needed any additional water yet. they don't use much until they really start growing. Even a week should be fine. At this stage to much water is not good.
If they are still dormant then you could just keep them that way - if they are in a plastic bag with wood shavings, or peat moss, they will be fine for another week if you keep them cool.
What I have been doing with the ones that I am going to be shipping out in a week or two, is keep them warm and moist until they show signs of a sprout forming, then move them to a baggie with dry vermiculite and put them on my bottom self where it is cool, so they slow down. (Its difficult to pack tubers with long sprouts on them)
