Here in the US a H14 mast tang is attached to the comp tip for the H16 spin (with stainless rivets and casings). It's included in the Hobie spin kit (which is actually from Hobie Europe). I don't see the smaller Hobies with spins very often over here, but I've never heard of a failure. Might the square top main add to the potential problem with the comp tip?
My 2008 H16 came with the Hobie spin setup when I bought it in 2012. I promptly removed it and sold it to a guy who was planning to put it on his H17.....I never heard how that worked out.
While these installation instructions don't actually include the H17, they are listed under the Hobie (US) product support page for the H17:http://static.hobiecat.com/item_attachments/40998010z52.pdf
The spin sheet routing in that diagram is way off, by the way, and there just wasn't a lot of good installation info out there when I was looking. There used to be a better diagram somewhere (Hobie Europe site?). I actually put together a pretty good installation guide with pics for my buyer, but it only addresses the H16. PM me if you'd like a copy.
Hope this helps....good luck!