Your confirming Wellington Marine
means that the boat is one of the ones I was thinking of. There were at least two of them built at the same time and the owners shared information during the builds. I very (very! once a year or so) occasionally run into the guy who built one using one of the other Wellington Marine
hulls and if I come across him I'll see what I can get from him regarding TinFin.
Not sure what happened to Wellington Marine but I think most of their work was associated with the marine slipway that used to be in Wellington. That closed down must be sometime back in the 1980's.
Your request as to what boats from designers to look for would result in a very, very long list ranging from very well known international ones through to very good designers who might only design one custom sail boat every few years.
What you need to keep in mind is that there have been very few cruising sail boats built as production boats here and none of those for very many years. While some designers have stock designs these may have been built by anyone including amateurs so the quality of boats bearing the same model name from the same designer
can be very variable (as is the case with Ganley's boats).
To give you a list would also run the risk of omitting some extremely well regarded designers (and who may have built the boats they design themselves too) of cruising sail boats such as Mick Orchard, Malcolm Dickson, Tim Barnett, etc who may have produced only a very small number of very well thought out highly regarded cruising boats. It would be a pity to miss one of these boats just because it wasn't on some list of designers.
My suggestion would be that any boat from a NZ designer
who can claim to have designed at least a couple of sail boats is worth considering with the main question really being who actually built the boat. Then refer back to the forum with builder
and designer's names.