Romantic Paternalism involves high investment colonies, so the basic thing is that it progresses towards three outcomes:
-Small nearby colonies with a land connection will simply be wholly annexed. We'd put in rail connections, we'd import our experts and work crews and we'd export their cultural and political authorities to our cities where they vanish. They'd dissolve entirely.
-Large nearby colonies will probably start eating their undeveloped neighbors after they get developed enough, Whether they'd split off or merge depends on events.
-Distant colonies will nearly inevitably develop to the point where they can seek independence and succeed. Historically the more exploitative imperialism models avoided developing colonies, focusing entirely on resource extraction, but they were forced by circumstances in the World Wars to do so, which led to being unable to keep said colonies later on due to losing the Imperial power gap.
So in practice, we'd grab something like 3-4 colonies at a time(unlike Protected Markets you can't realistically keep huge numbers due to the development commitments, whereas Protected Markets can keep as many as you can project force over), either devouring them entirely to help fund more colonies or releasing them over time into self-governing protectorates/allies as they grow too big.
