I don't deal with either so i really don't know. Well my longest carpet is an ij/coastal but seems to of topped out around 8.5ft and my pure jungle girl is heavy than her, just not as long. if you wanted an albino they originated in darwin's but are being out crossed to other subspecies. A big coastal might be on the line of what some people will call controllable or not. Just do your research if that's what you are considering.
they are under 1k right now, hardly an arm and a leg and like every morph they become more affordable every year. He specifically wanted an animal that is more on edge. Not that I've handled a lot of boas, but they have mostly been pretty calm. Carpets on the other hand, being on edge I would call normal.