J Tech Laser integrated with X-carve grbl (Inventables/Master version 1.0c)

In my experience you have to set the range that the pwm outputs. For example. My spindle is capable of 13,000 rpm. So I set the spindle range from 0-13,000 in the config.h file. This would then take the 0-5v pwm signal and chop it up from 0-13,000. So if I wanted to run at 6,500 rpm I would program that and the pwm output would be 2.5volts.

In spindle mode, what is the range that I should program to?

Would it be possible to get the arduino files so I can adjust as needed and then generate my own hex file?

Thanks!
Tim