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At this point, I am simply asking a question to confirm my observations.
I'm configuring an install of JS that will use multiple profiles. I see that there is no way to set a specific profile as default. The default, as I see it, includes ALL customized fields and is selected when one of the configured profiles is not selected.
if you create multiple profiles then the user must select one of them in the list at the point of registration. You are correct that you cannot make one of the multiple profiles the default