I decided to go from the TD into Urban Tracking and save the TDX for later. I did some urban with him last year, and he worked really nicely on some hard surfaces, and very short, contaminated (by people and vehicles) grass. I am insisting on a down at the article, and as he already has an excellent and fast 'down', this is not difficult.
Gone is working at any length over 12 feet right now. I am staying very close to him, usually under 6' and watching every little movement. I will not allow him to wander off the track for any reason, by giving him too much line. The communication through the line this way, is much clearer, I think. Of course, he is rewarded with lots of praise, and treats, from my hand, when he indicates articles. At the end of the tracks, which are also shorter in length for now, we tug and toss the last article.
He almost immediately "changed his style" which I am really happy with. The nose stays down, and he is really pulling along and sticking to the track with more determination.