Add ability to never go into standby for GMMK Numpad, or do device specific standby on mouse

Currently I have an always plugged in GMMK Numpad and a Model O wireless mouse. I want the mouse to sleep after 10 minutes, but want the GMMK Numpad to never sleep because the first keystore after sleep is not detected.

With the current configuration settings, this is not possible. If I set the global "Lighting - Turn off after inactivity" setting ON to 10 minutes, then the GMMK Numpad also sleeps after 10 minutes. There's a Standby option for GMMK Numpad where you can select either "Inherit Global" or "Device Specific", but if I select Device specific, I am required to select a value between 1-15, when I would really want to set it to never go into standby.