As Fr Keith Newton puts it:
"I’d guess it will be about two dozen groups. Mostly around the South of England in the province of Canterbury; some in the North but not many. And about probably between fifty and sixty priests."
See also his remarks about liturgy.
No mention of how many laypeople. And a frank admission that the decision to create an Ordinariate for this particular constituency, in no sense one for which this provision was ever designed, is about preserving the Anglo-Catholic subculture of London, of certain Oxford academic institutions, and of the South Coast. We all know what that means...