feeding them might speed it up some. From what I've been reading on them they occur in deeper waters and it is believed they rely more on food particles and less on light than other palys (although they are by no means NPS)
So if I remember I drop them a bite now and then. They seem to enjoy it. They don't spread at record speed but I gave one polyp away and thought I had to make do with fewer polyps but within a couple of weeks it popped out another. I am thinking the extra feedings might be key in case you want them to reproduce faster.
Yours are beautiful though!
Mine are just the typical cinnamon and white ones