I get them from Costco also, but separate them, and then vacuum seal separately to freeze. Then I can take one rack at a time and put in fridge the day before, and they are ready 24 hrs later. No problem so far. When repackaging you will have to put a folded paper towel in open end to catch the liquid before it gets into the area you are sealing.
Any reason you just don't cook the 2-3 racks and vac seal and freeze what is left over in the portions you desire to reheat?
I don't find that left overs, frozen, and reheated are anywhere close to eating them fresh cooked.