Very fiddly. Made an alloy plate to fit inside the tab (for the rivet to pull back against) but the hole must have been too large as the rivet pulled through the plate. Drilled it all out and started again. This time cut 1/2" holes in top of tab so I could see. Made 1/2" square plates from SS and drilled to be a very tight fit on the rivet.
Sanded under horn and flocked the horn and the rivet plates before riveting. All pulled up well this time.
Filled the access holes and sanded smooth. Horn all attached.
Servo fitted, rod fitted and all tested. Trim tab winds up and down and works well.
