I made up some foam ribs to cap the cutout in the rudder, similar to the ones used in the tab itself. I was also concerned about how much the skin was flexing at the servo but some experimentation showed that a rib on the servo cover, pressing against the servo, would stabilize the area, so I made up the rib as well. The ribs were bonded with epoxy and then the external surfaces were coated with flox, which will be sanded down to smooth the edges. The rib on the servo cover will get sanded and capped with a rubber seal to protect the servo. In between times, I also installed the fuel and oil pressure senders on the firewall.