It seems to me that you are only getting half your movement because of a previous "fix". This image shows what appears to be mild steel added on inside the "U" that attaches to the crossbar. I think that this part of the connector needs to be rotating around the end of the crossbar. The mild steel is preventing this.


Did you say that you switched the connector around so that what is on the rudder arm is now on the crossbar? What if the longer "U" section was on the crossbar and pivoting cleanly around its tip? Is the mild steel preventing this switch?
Here is a picture of Airborne's.


It seems like the longer U is on the crossbar.

Here is a page out of the Nacra Manual. In image 13 you can see that they don't even have the U around the tiller. Just a bolt through it(the hole can be seen on Airbornes photo) All rotation is around the end of the crossbar. So you have the upgrade kit, it has been welded, killing rotation around the rivet, and put on improperly?