It's a slick system but tight mechanical tolerances are required to avoid free play in the surfaces. Also it's much more tedious to adjust the control surface throw. if you want less than plus or minus the full servo wheel angle. What you need to do is alter the bend in the activator wire where it crosses the hinge line. But that means extracting the wire by some means which pretty much implies that you have really good access to the servos and activator wires. It may even require that you can remove the control surface via extracting the hinge pins.

It's a very slick system but as I hope you can see it comes with its own baggage that complicates the use of it.