After reading through the forum, I found the link to the tuning sliders and made a copy from your Thingiverse design.
I have printed them, and could use some guidance as to how they will help adjust the feeding. I was having problems with 3 & 4 sometimes both feeding and retracting at the same time. I took the 3D C apart to check to see if I could see anything wrong, and in the process a pin that holds B and C together broke. I found your 3DChameleon B/C Replacement Parts with PTFE Grip
I have printed new sets using that design. I am still in the process of getting everything working. so am going to replace the PTFE tube with new ones, have ordered spare springs ( they like to run away) for the unit and spare bearings so that I can assemble different sub- assemblies to test the tuning sliders. I think the new version that does not use the ferules will be much better. I was wondering if you could do a video on cutting the groves and how to determine what the sliders do to change the feed tension. I find a lot of the users are having similar problems and the information is somewhat scattered in the forum and in the you-tube videos. I watch a lot of the MK2 before I realized that I received a MK3, this is understandable due to the great upgrades you have done, but for someone not familiar it can be confusing.