On Sunday, July 3, 2016 at 11:28:45 PM UTC-4, Andrew Helwer wrote:
The option presents itself when assigning values to the constants in your model. If you select "Set of model values" you have the option to check a box making it a symmetry set.
Ah, thank you!
The only place where I had seen "model values" mentioned was "Model Values" in the "Advanced Options" tab, and I hadn't noticed that model values could be also specified by making a declared constant a model value.