[Piotrsko]

Comment: if you shorten the tuft eventually the tuft mass will be too stiff to respond. Perhaps change to fluorescent colored very thin sewing thread. Afaik, the boundary layer is still thought to be only molecules thick and any taping of tufts will affect that.

Traditionally, smoke or dust or exotic concoctions are used to show affectation of the boundary layer to airflow.

You are definitely looking at the transitional layer which for all intents and purposes would be close enough. Remember there are airfoils which are known to be turbulent but are lower drag than laminar.