Hi Mike,
It ain't my project mate, I've just been trying to help Marco Greco, an Italian modeller with the project, however good to see your interest rekindled. Yep Ta Moko is a scarification process that gets deeper and more apparent as the wearer ages it seems. Would be great to see you tackle this one again, do sing out if I can help in anyway, there are a wealth of examples you could use and a few of which you will see on the links I've provided Marco both here and via email.
Appreciate the post and by the way not sure if you got my message ref the Optio bust, I did replace the feathers as you advised, too mixed response. Personally I reckoned the look better.
Kind regards,
Mike