This is great. I am updating the C270 web cam optics module for version 7 of the microscope to be more the same as the Pi camera version. This will give a lower magnification, similar to the Pi Camera basic optics version. Your first photo shows both the C270, and the Pi Camera mounted in the microscope, how do you find they compare in use? Previously people have said the C270 magnification is too much, which is part of the reason for modifying it. (eg USB Webcam Lens Spacers and Camera Platforms)
Current progress is on Gitlab at Lens spacers for C270 and Arducam B0196 (!309), there is a view app button 
that will take you to the instructions for that merge request. The most recent STLs are linked in the customisations page.