Several methods of deriving an expression for the spray cone half-angle of a swirl atomizer are presented. Expressions found in the literature, based on the inviscid theory, together with suggestions for improvements, are given. The theoretically derived functions for air core diameter and discharge coefficient as functions of atomizer constant that were presented in Part 1 of this article series are charted and compared with experimental results from the literature. Also, the various functions for spray cone half-angle, as a function of the atomizer constant, are charted and compared with the experimental results from the literature. The fit of these theoretical functions with the experimental results are discussed in terms of the flow physics and the limitations of the inviscid theory. This comparison leads to the conclusion that the inviscid theory may be of benefit in the basic understanding of the flow physics of swirl atomizer internal flow. However, it is of limited value for detailed understanding of the complicated flow regime as it does not consider variations in the supply pressure, viscosity, turbulence, wall effects, or fluid-gas interactions. It does allow ballpark estimates for flow rate and for air core size.