One other thing... be aware that shrinking it enough so everything fits the Tree's mini display will make the font pretty tiny... possibly to the point of being unreadable, making the display of track info in that location not very helpful. Also, shrinking things to fit for the Tree mini display will also shrink it for the Playing Now display (you cannot control them independently) which looks pretty silly in the Big Playing Now display.
As you noted though, much of data shown in (many) Track Info templates is already shown in the Player Bar's display anyway, which you can easily edit on the fly to customize whatever text tag data you want without having to edit an HTML file. That said, I don't really use TI's and thus don't appreciate other's desire for them... the only thing I care to see in the Player Now display is cover art and lyrics, or a visualization (Milkdrop2, SoundSpectrum's G-force/Aeon, or even a couple of MC'S built-in visualizations are pretty good).