IIRC from the “What we left behind” documentary, they were shot on film. They even had a few minutes of HD material scanned from the film reels. It’s the CGI that was baked only into the tape version that makes it so difficult to do a HD remaster. And why they went back to the tapes when producing the DVD release.
IIRC, the first model ate mosfets for breakfast because the photo resistor is way too slow going from illuminated to dark. That leaves the mosfet in a fairly high resistance state for an extended amount of time during which it dissipates a lot of power. You should add some kind of Schmitt trigger inverter that buffers the resistive divider and gives you a clean narrow edge to drive the mosfet gate. A 74HC14 together with a 7805 voltage regulator should give you enough output voltage to drive the mosfet. These chips cost less than a single replacement mosfet and you can drive 6 coils with them.