I've also seen people attach a tie wrap and rotate the head around to find the light side. Seems easier than moving a piece of tape.
The guys using the zip ties don't leave the thing on there. LOL They use the 'knot' of the tie wrap to find the place to add weight, THEN they start adding tape.
And ya, I would have thought T-motors would be good to go. Here's a guy balancing t-motors with tape:
http://www.youtube.com/watch?v=HeopBB_i8ng
At this point I don't know who to believe on this one and that usually means I need to test it myself.