If you don't want to go with the number row on the original 'secondary' mock up:
Can you consider making the number row the same style as these? Centred lower legend with split upper legends:
The design from the imgur album, with the empty space on the top right quarter, makes my skin itch
In my opinion on this style of number row:
It will look strange if you wanted to mix them with any of the international number row keys (which have centred primary legends and secondary legends off to the side).
If will look strange if you wanted to mix them the included numpad secondary legends.
There is no 'offset' version of the backslash key, so it would look strange with a split backspace layout (on the HHKB layout backslash has a secondary function on insert, tilde has the function of delete).
Basically, style wise they are not mix and match like all the other secondary legend keys
The ability to use a mix of kits to fill out any keyboard, due to the uniform profile and aesthetics, is one of the biggest achievements of the granite set
Just my 2 cents