I typically install blocks under the jacks and then dump the air bags to remove some of the load from the suspension. In reality, it is probably overkill because I believe exposing the cylinders to the elements will most likely do no harm. I say this because a large portion of the three hydraulic rams (left, right & raise cylinders) on my 1973 Bombardier track driven snow plow are always exposed and have zero rust on them. Not only are they 40 years old, but they have also been exposed to all the salt used on NE roads.
Lou
05 Travel Supreme Envoy