You can lower your cost considerably by canabalizing a $25.00 New Bright RC Truck available here in the States at most WalMart and Toys-R-US retail stores. They come with a mini wireless controller and a small two channel receiver that with minimal effort can be modified to control any number of servo. Most masks I encounter are cast so thick, you only need the servo to open outward or pull back, the masks elasticity typically pulls the fangs back to the position you just pulled them from. You can easily modify the controller to fit into your gauntlet or belt. In my most recent build, I replace the transmitter's slide switches with contact switches and embedded them into my right gloves fingertips, after waterproofing them. The entire set up is wireless. So, non noticeable taps of my right hands fingers control the upper fang pull backs and lower outer mandibular spreading. My actual jaw opens and closes the masks true inner mouth jaw. Grusderks mask is pretty wild, however I was always put off though, by the wearer's inability to manipulate the fangs and mandibles while keeping the inner jaw/mouth closed. Just my 2 cents! Pete Mander originally gave me the idea to use the inexpensive RC toys transmitter and receiver and I have to say, it's works like a charm! Years ago I was fortunate enough to pick up an unfinished P1 fully animatronic rig created by Pete. He had built it and installed and wired 7 servos, they controlled browe pull up and down, upper fang pull back and lower outer mandibular spreading with independent fang extension as they spread (so the lower mandibles open out and fully extend). To date, it's the most anyone of us has ever animated a mask. It is truly work of art. Pete and I share a facination of animatronics, and I consider him a friend and colleague. When I received the mask, I needed to add a power supply, receiver and transmitter. I had it up and running in about three hours. I sold that rig a few years ago to a fellow Lair member. In the years since then, I have resculpted the fibreglass underskull that Pete originally designed, based on the Gillis/Giler AVP rig, to a more generic shape so it fits under a wider variety of the masks in my personal collection. Here are some shots of Pete's original rig, hope they help...
Kindest Regards,
Alan