Except you don't need a 100% return to get maximum sharpness. If a lens reaches peak resolution at f/8, it will peak at f/8 whether it's mounted on a 4MP or 40MP camera.
In any case, the variance in resolution from f/5.6 to f/11 on a 24-70 is negligible and likely not noticeable in actual use.
Well, but an aperture smaller than the DLA cannot give you the peak sharpness.
Unless the difference in the lens' sharpness is quite large.
But assume your lens has its peak sharpness at f8.0
Then shooting at anything above that can be be worse or be equal - agreed? - now if your sensor has a DLA of f9,3 shooting with anything above 9,3 would be worse - and the OP used f11, as he stated, in his test image - hence he couldn't in any way get the peak result.
Or am I missing something?
And the way I understand the OP he want to know how sharp it can get - as it doesn't seem sharp enough to him.