Hi Kiwikermit, I would recommend getting your cambelt checked if its had any money spent on it for piece of mind.
If its standard the 90 degree rule would be fine though.
The first cosworth I brought had the cambelt one tooth off on one of the cams and took ages to diagnose what the problem was.
I am not sure if it was installed incorrectly or if it jumped a tooth.
Most engine rebuilders / decent mechanics would have a tool that checks it.
Where abouts are you in NZ? I use Manon Butler in Takapuna in Auckland they have been rebuilding cossies regularly for years.
I took a photo last time he did it. Burton motors in Sunnybrae are also well experienced also in Auckland.
Hope thats helps,
K