The only advice i can give is to ring hobie uk on 00441202 671661. They know of alot of the 16 owners in the uk and may be able to point you in the right direction. Failing that just ring up the people on the various for sale lists for the uk (this one and www.catamaran.co.uk) a bit nearer the time and ask nicely.
As for boats there sould be in the region of 20-25 hobie 16s but the event is huge with up to 20 spitfires possibly 50 f18s and a few f20s aswell so the socials will be good.
Good luck
Ben