Before you go all crazy buying all the different parts, it is a good idea to print the entire thing to get a good feel of the remote. The remote is a thumb-based design, based on the Boosted remote, that for some don’t feel quite right. A trigger-based design could be released in the future.
Now let us get to business. As mentioned earlier all 3D-printable parts can be found on Github in the STL format.
When printing the parts I recommend printing the enclosure (top and bottom) facing down so that you won’t need any support. Use a high infill (+60%) and a low layer height (100-200 microns) to get a nice surface, and a strong remote. The material isn’t crucial, nonetheless, a carbon infused PLA adds that extra bit of strength, and give the entire build a more robust fell.