You don't need this mod. BambuLab now sells their 4-in-1 PTFE Adapter which serves the exact purpose of this mod.
I just happened to have an extra AMS hub LITE lying around, and seeing as how the hub LITE and the 4-in-1 adapter are the same exact product, just with slight alterations, adapting it to become a 4-in-1 adapter was an easy process.
Just depress the black end of the PTFE tube coupler and slide it into the model and the AMS hub LITE. The model will keep the black end depressed, which is essential to stop the PTFE teeth from interfering with filament input. Use 20mm M3 bolts to attach the hub to the back of your printer.
You can find other models I have released for the X1C/AMS here:
https://makerworld.com/en/u/2811301167/collections/109412
If you appreciate my models, please consider buying me a coffee!