I made the tab out of .063 aluminum 3" X 14". I placed it a little in from the tip so that if it doesn't have enough effect in flight, I can put a larger one in it's place. To get enough room, I drilled out 3 rivets from the nose skin and put nut-plates in their place. Putting a nut-plate in the center bottom was a mistake. It interfered with the rod.I see now that the Servo could have been mounted a few mm over so that the rod and nut-plate would clear.
Cutting the outlet for the rod was the hardest to get the right size. I made 3 tabs for the rod to connect to the tab before Getting it right. The "olfa" knife is great for cutting a straight line in aluminum sheet. The travel is 26 degrees up and down. This can be done retro-fit. There is room for the wires behind each rib.