Those red rainbows -- Irian Rainbows? I think they also call them "Salmon Red" Rainbows. They can grow 6+ inches. If you plan on keeping them, you might want to beef up that school to 6, but I wouldn't do both the Boesemani and the Irian. The Boesemanis can get anywhere from 4-5.5", depending on the strain.
Roan