Any tips on how to fix the tiny ferules on the 0.8 mm wire linkages
Soldering will do nicely Phil. Don't worry about the G/F horns, just like committee members they can take the heat. So make sure that the z bend is at the servo arm end!
I'm not at that stage yet, but you could also try a crimp prior to soldering for 'belt and braces' approach. However, I'll probably put a z-bend both ends. Get it all lined up before gluing the horn onto the control surface.
I simply made the first 90 deg bend with pliers then the second of each Z bend by hand. after installation of horn and servo. (Z bend pliers make too large / wide bend causing excess slop)