With all of the FEA (finite element analysis) software available to model glass flexure, these simple windows of non optical quality being an academic exercise, hope the windows photographed by Harry C, and thank you for sharing, are not representative of the quality of glass which will installed.
The glass used for the windows showing stress that is being induced by both the mounting points and more than I would like to see, along with worst, high levels of surface irregularities that appear to be inherent in the material. The stress (presuming a float glass process) appearing to be a function of irregular surface cooling or too rapid a cooling of the surface, like a cost reduction measure with the gas furnaces, or too rapid a manufacturing line, resulting in large thermal gradients to form between the first and second surfaces, the deformations becoming trapped during phase transition (solidification point). Thus, leaving the glass with a very high level of residual stress, a.k.a. full of ripples.
In addition, wonder what the glass looks like up close, and if the glass is relatively free of bubbles and striae?