Found this thread while looking for something else, and hey, we actually have something resembling an answer to this one! Not a population number per se, but 7.1's MSQ gave us something.
Fake Sphene tells us that there's going to be neo-regulators allocated to five thousand people--and crucially, that the reaction to that (by the millala specifically; Wuk Lamat's more responding to 'that's not the entire population and Sphene wouldn't call close enough good enough') makes that sound like a pretty small proportion of the population. So I'd say we're probably in mid-to-high five digits, the low 100ks at most.