Everyones postings using external control rods will work just fine.

If you wanted to use your original idea of a torsion rod, you can do it as long as you use a bushing (brass eyelet or tubing) and a soldered washer for a positive stop. The key is to have the pivot point of the tail wheel match the pivot point of the torsion bar as shown. Using a Sullivan tail wheel is the easiest because it comes with the spring.

John