A lipo at the load expected at full speed cruising will be around 3.9V/cell, and that's probably a high (safe) estimate.
Don't use resistors. Limiting the throttle throw after calibration is much better.
The interesting part is that Castle could fairly easily program in a rev limiter that is adjustable through the Castle Link. But, they haven't.
They also haven't got the ESC to work with other brushless motors.
When someone is intent on excelling in an otherwise laudable manner, does he not desire to inflict pain on others by means of his exalted status and enjoy the envy he arouses? Is there not an anticipated delight in an artist's ability to defeat his artistic rivals, which heightens his euphoria in creation?