Seven years I had a building built 14" tall so I could get a larger RV at some point. I knew nothing about doors, floors and sidewalls, but I told the large building company what I wanted. Bottom line...
JMO, but I think I would more concerned with whether what I want to buy will do what I want, more than whether it will fit in my shed.
Don't get me wrong it's nice to store indoors, but you're buying an RV to use, and compromising on that, just so it will fit seems backwards to me. Unless of course you have no other place to keep it. Or if you're only planning on using it a couple times a year for a weekend.