Exactly what I was looking for to get the buffer a bit more stable. I printed both arms and hoped to use all three (incl. the original one) for even more stability. Unfortunately, the PSU cable was in the way because I use my buffer upright. So, I ended up using the shorter one and the original arm. However, the arm with the motor cutout would work flawlessly,

First picture: Two of the design, as posted, before tuning pressure advance.

Second picture: An enlarged make, came out a bit smoother with better settings.

Third picture: My first use: two enlarged makes, in use to help spool new sisal twine onto one leg of my cat tree.