I think is fine, i do not like to start big either, would get a pass around 2"-5". If you have ever had a 150g you would know that 150g isn't really that small.
Mono has most red underbelly among all peacock bass cichlids, ocellaris has red and green, and orino is the greenest.
I like Orino, but its really hard to find and expensive, thus i am getting Ocellaris.