Thanks for the kind comments and Well it's been a interesting day for Fate after a few months away from this thread it spung to life and I've got a few PM's outside this thread if anything I'm a little shocked to see doctor fate getting his well awaited come back.
There will be some more updates to this project soon regardless but I'll just leave that report for another time, but on to answering some questions.
As for the bucks which I think are just molds actually they are cut right down the center, used a japanese flush saw less then 2mm wide and took about an hour or longer to cut through, tedious but effective as the mohawk/fin and tapering face makes it super easy to hide were the helmet seems together.
As for vacuum forming I have always thought it was a cool way to build armored parts but mostly cause it is alot smoother/uniform and I really find the High impact plastics are so much better to work with then other materials and with out a injection molding machine casting with these type of materials is out at the moment, I'd recommend it to any one of interest.