fledermaus

I am working on a design for a flying boat with its single engine mounted on struts above the fuselage. I plan to use a 0.46 2-stroke in this, because I have one lying around not doing any useful work.

Question: how much strut is enough to keep the engine mounted to the fuselage? I figure it will have to be a metal strut with wooden fairings, or perhaps an airfoiled hollow metal pre-formed strut. Any ideas?

BTW, the plane looks like this (it's the fictional flying boat from Miyazaki's movie "Porco Rosso" incidentally, not a real "Golden Age" plane but quite a believable interpretation of the concept).

Thanks for any suggestions.