It's hard to make a lens sharp over its entire focusing and aperture range. Extending the focusing range way down, for a fast lens that wasn't designed to do that (at significant extra cost), is likely to bring out a lot of aberrations. Also, the 56 f/1.2 is one of those lenses designed to create smoother bokeh, right? That has to be done either by introducing aberrations, or a plate that shades the edge of the light path, or both. After all, the visible bokeh is just bright spots that are out of focus, so if you want those to look different from a sharp image of the aperture, you have to introduce aberrations for the images at extreme focus positions. Just a general comment. I have never tried the lens you mention.
The 60mm, although very sharp, only goes down to 1:2 and doesn't work well with tubes. Look at the laowa 65mm. Totally manual, which doesn't matter much with macro, does 2:1 and is very sharp. At least mine is anyway.
