Yup Janne probably has more DIY experience than the rest of us on this site.
His projects, and his father's, are a great way to learn how to scale up the pitch control systems you have.
Janne has posted many photos and videos of large turbines. They include detailed discussion about pitch control (mostly of the passive variety). Also, you may take an interest in the member "Menelaos" who also experiments with these.
In case you haven't found the feature on the forum, you can examine each member's previous postings by clicking on their name, then searching for "previous posts by this member".
Funny, I just realized that you and the other two members I mentioned are European... How come none of us in the Americas aren't all making pitch-control systems? Eh?