Im curoius how my buddy does it. He gets the sunbursts in his farm to split regularly like once ever 8 weeks. They seem to multiply like rabbits. He used to cut them but then found he didnt need to. It has something to do with how he feeds them or something. Wish I had more to share on it. Ive never had one split on me like others they just get bigger and more yellowish orange.
Khalis had a trick for getting nems to split. He would basically stress them out, I forgot how exactly, and then do a large water change, and that would trigger the nem to split almost every time.