I'm having issues with outer wall zits on my CR10 when printing at high speeds and I feel like I've tried everything resolve it. I believe that the problem lies in how Cura handles pathing at wall changes. Not every model has good corner to hide a wall seam.
I have no coding experience but I've attached an image to help illustrate my solution.
I've enabled "Optimize wall printing order" and "coasting" which makes things easier to see.
Fig 1. This is how Cura currently handles inner to outer wall moves. The nozzle moves to the end of the path and makes a hard 90 deg turn to reach the start of the next wall. I've also noticed that Cura treats this tiny move as a travel. In my case, travels are set to 160mm/s. I believe this fast sharp turn is what causes the zits and is exacerbated by higher travel, jerk, and acceleration speeds required to print quickly. It's further exacerbated with "optimize wall printing order" turned on because the zits stack up.
Fig 2. My proposed solution with coasting enabled: Instead of the sharp angle travel at the end of wall 1, run a coasting (NOT travel) path directly to the start of the next wall. This would greatly reduce the sharp angle and resulting vibrations at the start of the outer wall, especially with the currently available option to reduce the coasting speed. Finally, at the end of the outer wall path, follow a shallow angle back to the inner wall to prevent visible bulge at the end of the path before travel or retraction
Fig 3. An example of this method without coasting volume. Offset the start/stop points of the inner walls based on the desired placement of the outer wall seam (if using seam alignment that prefers corners). This still allows for a non-extrusion coasting move that takes a shallow angle path to the start of the next wall. End the outer wall path with a shallow angle coast back into the inner wall before traveling.