Hi Erik,
I went through a similar exercise when I acquired my Canon 5DsR and comparing to my Contax 645 IQ160. Adjusting distance for equivalent lens focal lengths and format differences as much as practical, I used a Sigma 70mm F/2.8 macro on the 5DsR and a Zeiss 120mm F/4 Apo Makro Planar on the Contax.
I was shocked how close the Canon system came to the Contax in terms of resolution. So much so that I was "forced" to upgrade to a IQ180 to maintain a more clear resolution advantage. ;-)
Maybe a 60MP XF system might show a bit more resolution advantage than the Contax, but it's clear to me that The Sony and the Canon are defintely in what was exclusively 39-60 MP MFD territory, resolution-wise.
The attached jpegs are 100% crops of my test. (Grayscale just save on space) Looking at the images at 200% is really the only way to see any differences, and others may even disagree with me on which is actually sharper.
Regards,
John