Scotmac,
I'd wrap the slabs, individually in some heavy duty foil with a little bit of apple juice and throw them in the oven for 20-30 minutes. Make sure you seal them up real well to preserve the moisture.
I like to put my ribs in a foodsaver vacuum pouch after the first night's cook. Then I freeze real quick. I usually add a very little amount of apple juice. If you put them in a foodsaver pouch, you can throw them into a pan of boiling water and they come out just like the day you cooked them. My foodsaver purchase was one of the best buys I've found for my Q'ing pleasure.
Happy 4th To All,
C'Nooga