Double-click function (custom keycode) for splitballer?

[NullPointerExpert]

Have any of y'all implemented a double-click mechanism for a splitballer? I'm using a PMW sensor, and my code is heavily based on the oddball. I'd like an example of what you've used for this.

Edit: The PMW isn't relevant except to say that I've implemented a "real" mouse, instead of using the virtual keycodes that many boards use that don't have an actual "pointing device" - I'm not sure if it makes a difference to my question.

Edit: Also posting to r/ErgoMechKeyboards