On the print/syreq, scroll, pause/break style right block is it possible to have the bottom right key blank key be “numlock”. What I envision is when this key is toggled (not held), the right block becomes 789 456 123 with the left blank now being 0. This way numpad functionality can be toggled. Is this possible? If it matters I will order the hhkb both split layout.
Yes that is actually how I personally configured my F77 prototype, except in reverse (numbers are the main keys and the function key held down will activate Home, Pg Up, etc.). The factory will have a default configuration for each keyboard but you can easily do what you are looking for with the xwhatsit GUI.