I have had most of my planes hang by its tail (nose down) for some large periods of time (I have 15 years in the hobby), let me tell you what I have heard and done succesfuly. When you know that you are going to put a plane a side for a while, then take out the glow plug and fill the head of the engine with transmission oil, use something else to cover the hole of the glow plug (Put the glow plug somewhere else and where you can find it after works or in spring time) then just let the plane hanged by its tail. The transmission oil will preserve the engine for a large amount of time.
When ever you feel ready to use your plane once again, then open the glow plug hole and drain the engine, put the glow plug again in place and your engine will start inmediatly, just like the last time.