I'm really happy with what came back. I think it's a great that Dirk was willing to sign a jersey, and the jersey's Dirk autographed have all seemed to come back with a nice signature instead of a scribble. It took about a month and a half to come back.
The Dirk Nowitzki ttm address I've used is:
American Airlines Center
2500 Victory Avenue
Dallas, TX 75219