12 hours later that task was DONE! Woke up early, worried about the geometry of the trim tab swing since the top and bottom edges are not perpendicular to the pivot axis. So we invested an hour in a rough mock up.
Now it needs some edge smoothing and figuring out some carbon layup to reinforce all the newly exposed edges. Since we couldn’t cut the rudder on a curve around the pivot tube we need to add back some little wings to cover up the hinge, in terms of keeping good water flow between the rudder and the tab. That should be mellow work, coming off the stress of getting this whole thing built and cut right :)
Try this link to see the trim tab in action: