On the tail wheel - I've done a few and I've seen all kinds of approaches to the steering problem

On mine in the picture I made a longer wire to go up and bend 90 degrees and epoxied into the rudder.
You have to have a bearing support up through the fuselage that aligns with the rudder hinge line

But your rudder hinge line is not perpendicular to the bottom of the fuselage???

I have seen one guy with a separate servo to run the tail wheel

After looking at the Tower Trainer, I would use the Dubro bracket.

Make a plywood shim to angle the bracket to where its pivot axis is the same as your rudder hinge line. Make a new wire for the bracket that goes up and is epoxied into the rudder