My bike sat for a year with no special prep while I went through a clavicle nightmare. I couldn't pull on a wrench for nearly that time either, but when I finally pulled the top end off the crank had a nice coating of oil, no rust. I've used this exclusively for over ten years in my three GG250s, my wife's Pampera(at 80:1), and another GG125.
The oils you have to be careful of as far as rust are the ester base oils, like Motul and Redline. While of the highest film strength, ester is highly hygroscopic meaning it absorbs moisture from the atmosphere. A true racing oil but no good for storage.