I am out of home for 3 more weeks, I will post some pics then.
But basically I did as Skypirate mentioned. Tape upper and bottom side ...
I was planning to do something wich would look more "professional" but since the tape is doing the job ... It will stay!
I also found that gap tape on the elevator of my Mk 3 made a huge difference.
I used 3M book binding tape that is clear, and doesn't show. I did the entire length along the elevator, but left gaps for the hinges. I also used SkyPirate's application method which worked really well.
I didn't do the rudder, as I don't feel as if it needs it. Happy to be persuaded otherwise.