This is my take on the tool holder for my Katsu (Maktia RT070 ripoff) and fits the 25 mm version of the MPCNC.
I designed the tool holder so that it'd get as close to the center of the z assembly as possible to gain rigidity. (Not using the original tool-mount plate)
Since I used hex-socket screws which have a rather long head, I filed them down to be able to get even closer to the Z-conduits. Not sure if this is necessary if using standard hex-heads.