Hi @Wolfie,
Yes, your proposed solution should work.
The ESC has a signal deadband of ±25µs, and I believe there’s some buffer built into either end of the analog reading used by the Thruster Commander firmware, so the resistances may not need to match perfectly. That said, having a close match wouldn’t hurt.
Alternatively (if you have an Arduino or similar) you could reprogram the ESC firmware and turn off bidirectional mode, in which case the standard potentiometer setup for the Thruster Commander should work as-is - no extra resistor needed. These instructions may be of interest.