Since the manual isn't clear on the fuselage side skin spacer and gusset placement, here's the info.

From the factory

Also check out Peter's log entry for the bigger view of where they all go.

Also, I've updated the Links page as there are some new builders with blogs (if you're out there building a Sling and I don't have a link to your blog, please let me know!).  There's also a new Sling builders page on Facebook that is linked there.