Let me add my welcome!
It seems you really have your work cut out for you with this refit, but it also sounds as if you're cut out for the work too!
It must be handy having your cousin as a resource. That was quite a trip they took in their CN58. Looking at the track of their journey, I couldn't help wondering if they ever regret not having crossed their outbound route to "close" the circumnavigation? From the looks of it, one long tack to leeward might have done it!
Do you ever kid him about it?
All the best of luck to you with the refit. We don't have too many boats your size here, but I hope we can be of assistance all the same. And maybe you can teach us a thing or two as well!