Hey.
My advice would be to really really really set aside that wish for .... say... 3 months and then revisit it.
1st: there isnt much info out yet regarding templates etc. Waiting (more then 3 months probalby) will give you a more accurate prop.
2nd and more important reason: The new Boba helmet is new and exciting. Wait if the desire for one may not go away. It coul well be that you regret overpainting a perfect old trilogy Boba helmet.