AutoHotKey is available for free and can be used to create a wide range of keyboard and mouse shortcuts, hotkeys, and macros.
The syntax to set the Volume Up with WinKey + Wheel Up would be #WheelUp::Send {Volume_Up}. After installing AutoHotKey, enter that into a blank text document and save it a 'fileNameHere'.ahk, then double click to run it.
While I am not using it currently, I have used AutoHotKey quite extensively in the past. Check out my GitHub for some examples of what you can do.