make the huion h610pro aka monoprice scroll using the second button. I've chosen to only track vertical scrolling, but it would be easy enough to track the x motion of the stylus as well.
I set the config (in the huion driver) to have this button emit cmd-shift-option-/ (slash) and this runs in hammerspoon
Install hammerspoon put the enclosed file in ~/hammerspoon/init.lua start hammerspoon or tell it to reload the init file.