Ignore the code for a moment, and answer the electrical questions.

The turret encoder goes high when active, but does it actively switch low when not-active?
If it does actively switch low (and not just go high-impedance), then it might be able to switch the SZGH inputs directly, but it'll depend on the actual hardware inputs as to whether they'll reliably switch when they're driven to 12V instead of being left open circuit.

As long as the electrical side is switching reliably, then swapping logic is easy enough. In that code sample you posted, you just need to swap the + and -'s