My mono pair started spawning at about 12". The male was easily distinguishable by the bump, nuchal hump, or kok, on his head. I didn't have to do anything special to get mine to mate, they just started doing it on their own, although it usually occurred after a water change. Really, they seemed to spawn similar to other SA/CA cichlids only they weren't quite as aggressive towards tankmates. I never did raise any of the babies, and now I wish I had since I lost my female a couple of weeks ago.
Definitely try to get a copy of Ric Perez's article. It's a great read.