Oganza,
I don't think your storage is a tough requirement. One big deal is to keep them in a relatively dry environment. You might give some consideration to putting them in polyethylene tube bags (purged with dry nitrogen if you pack them in a humid environment) after you've put protectant on them. I think if you put them in sealed bags to keep out humidity, any of the common products like RIG, LPS 3, or your favorite gun oil would work well beyond 3-4 yrs. Don't get carried away with oils or greases...remember, you are not putting anything on the innards and you expect them to survive undamaged, right?
I'd simply put some RIG on a patch and run it in all the bores and wipe on the outside of the metal, bag and purge and put them in padded crates.
