  We analyze measures of the azimuthal asymmetry, in particular the participant
harmonic moments, epsilon*, in a variety of Glauber-like models for the early
stage of collisions at RHIC. Quantitative comparisons indicate substantial
model dependence for epsilon*, reflecting different effective number of
sources, while the dependence of the scaled standard deviation
sigma(epsilon*)/epsilon* on the particular Glauber model is weak. For all the
considered models the values of sigma(epsilon*)/epsilon* range from ~0.5 for
the central collisions to ~0.3-0.4 for peripheral collisions. These values,
dominated by statistics, change only by 10-15% from model to model. For central
collisions and in the absence of correlations between the location of sources
we obtain through the use of the central limit theorem the simple analytic
formula sigma(epsilon*)/epsilon*(b=0) ~ \sqrt{4/pi-1} ~ 0.52$, independent on
the collision energy, mass number, or the number of sources. We investigate the
shape-fluctuation effects for jet quenching and find they are important only
for very central events. Finally, we list some remarks and predictions from
smooth hydrodynamics on higher flow coefficients and their fluctuations, in
particular sigma(v_4)/v_4=2 sigma(v_2)/v_2.
