Just a quick update.
We got to Orsorno and visited the guys at Motoaventura. Swapped out the rear for another K60 (it was their last one and earmarked for another fellow but the truck was arriving the next day with more so they sold me their stock). Great folks, coffee while waiting, chat to the mechanics and worked out pretty much the same price as back home (US$220 for 150x70x17).
They did mention that they are getting more walk in lately whereas they used to get emails first (I think they would prefer that) and this way avoid disappointment when you get there.