Just showing what's possible, I think an image I posted before:
24L Mk I, at F/3.5, APS-C, minimum focus distance if I remember correctly. This image I use often to demonstrate the tilt capabilities of this lens, and the awesome bokeh both beyond and before the (tilted) focus plane.
The 24Lii is even better. The 45 and 90 are absolutely great too. The only one I do not use for close-up and macro shots is the 17, although I shoot with it at close distance no problem, be it for other reasons.
If the magnification is not high enough, I never hesitate to use extension tubes, although 12mm is max on the 24L, as it si quite possible t have the object or parts o fit touching the front element , and/or extenders, especially on the 90.
In short, looking forward to these new lenses .
Kind regards, Wim