I don't know that there are any real differences between btas regarding how large they get. I have an rbta that's easily 12" across and refuses to split....I have a couple rainbows that split as well...one was about 10" when bit split, the other was maybe 4".
Aside from lighting, just make sure that your powerheads, overflow, and returns are protected to keep the nem out. In a small system, it won't take very long for a wandering nem to find its way into a powerhead.