  In this paper we examine the methodology for extracting the Knudsen number
(K) and the ratio of shear viscosity to entropy density (eta/s) developed by
Drescher et al. The final result for eta/s turns out to be quite sensitive to
Glauber parameters, and particularly the parameter x which controls the balance
between Npart and Ncoll. We also explore how alternative formulations of the
functional relation between the elliptic flow and Knudsen number impacts the
physics conclusions, based on Pade approximants. Finally, we extend the
calculation to include a limiting minimum value on the mean free path
proportional to the DeBroglie wavelength. These results emphasize the
importance of clarifying the initial state used in different calculations, as
well as the ambiguities inherent in using a transport approach in a
strongly-coupled regime.
