Making it clear that, when the toolbar is closed, there's no other way to open it other than the mouse ( which means in VR you should pay attention not to close it with the X button, because that would result in the toolbar closed, in VR only ), once you have the Toolbar icon active, GSX will respond to an Hotkey and the numeric keys.
This means, if you use any software that can convert speech into keystrokes, for example Voice Attack, it should already work.