My shed has a single door, so I can't help you with your query soz :(
You'd be surprised though, at how much you can cram into your shed and how easy it is to get at everything, as long as you don't pile everything in willy nilly.
Our shed is 8 x5 (or 8 x 6 - can't quite remember) and all our garden furniture is stored in there over winter:
BBQ, wooden table (folded down), 6 wooden chairs (folded down), a few plastic garden tables, approx 15 plastic garden chairs, 2 parasols, parasol base, numerous deck chairs/loungers, numerous seat covers, sets of cushions for 2 swing loungers, gazebo, fence paint and brushes .... prob a few more items that I can't remember at the mo ......
The thing is, over winter we don't need to get in the shed and over summer the shed is almost empty, it's just the putting in and taking out that could be a problem, so take care when putting everything away for winter and you'll find that when it comes to spring, it's much easier to get everything back out :)