So, I'm playing Fallout 4 as a bad guy and went the Nuka-Cola Overboss route. Now I've got several outposts located in the Commonwealth, each one set up with a Nuka-World radio transmitter, amplifier, pick-me-up station, etc. Each outpost has at least one settlement supplying it as a vassal (usually more) and happiness is up near 100 at each one. When in workshop mode, the top bar is green all across. Getting the raider "settlers" to show up, though, is proving a problem.
With non-raider settlements, once the settlement has food, water, defense, etc., settlers come pouring in fairly quickly. With these outposts, I'm seeing less than six raiders - and that includes the three or four I started with. I get that most, if not all, of the raider settlement system works more-or-less like the normal one, but obviously attracting settlers works differently.
In Fallout 4, what's the secret to attracting raider 'settlers' to your Nuka-World outposts?