I've stored a lot of enginss for several months, some for a year or two while working for my Dad. Removed from wrecks, overhauled or rebuilt and stored until sold or installed. Penetrating oils are not my first choice. They are thin and designed to seep, not stick in place.
My goto was, and is, a fairly heavy weight engine oil. Back in the day, I'd use STP to make it stickier. pull the plugs put a small amount in each hole. Turn it over by hand and repeat. PUT THE PLUGS BACK IN. Also plug all openings that connect the outside to the inside. Intake, exhaust, oil fill, breather tube etc. You do not want atmospheric moisture to access the inside of the engine. Always worked for me.
I have known of guys doing nothing and the engine was fine months later. Others found the rings stuck to the cylinder walls due to a fine film of rust.
keep it dry, either wrap well or keep inside under cover.