Bernard, I always follow your posts as I shoot the same combination as you. How many images are you taking for a DoF stitch? I'm finding three about the right number. An article in On Landscape, the British landscape web magazine (highly recommended, btw), by Hans Strand which convinced me of the efficacy in shooting f16. Now due to the bugaboo warnings of diffraction by various individuals on the net, it wasn't until I got the D810 that I started shooting f16 with the Otus. Oh, my. What a revelation.
As to the OP, I've shot with both the PC-E 24 & 45. The copy of the 24 I had, and there is apparently wild sample variation with this lens, was good for tilt but not shift - the corners were poor even stopped down. I tried several copies of the 45, the first was a rental and worked well, but when I purchased one the CA on the example I got was horrible and could not be fixed in post. I think if you read some of the tests of the Nikon's you will find that most users recommended that by not shifting to the limit the lenses were acceptable.
I saw an image, perhaps photo shopped, of a supposed Canon FF mirrorless with a TC lens. That got my attention.