I need some help to decide which spherical keys should be from row 3 and whoich should be from their native row.
All alnum and punctuation keys should be from their specific row (1-4). Some modifiers do not exist in the rows where they would be needed.
Also, the space bars are all from row 3, so bottom modifiers would be better from row 3 too. As a side-effect, they would be more thumb-friendly.
I recommend to do all fuction keys in row 3, because they are usually not touch typed anyway and it would allow more flexibility.
2 units keys are not available in row 1 anyway, so row 3 is the best choice for them.
What about cursor keys? I'd prefer them from row 4, but on the other hand, they are kind of function keys.
Because we will save some function keys, I could add both variants.
Another question would be what to do with the numpad?