I currently have a ball python, and I love it, but I want something a little more sociable. I am thinking about getting some type of boa. (it will probably be 6 months to a year before i get it, because i need to do research) I have thought of a few I might like, but I can't decide. So, I want to ask you. Which one would be good for me? Here's a little bit about what I am looking for:

-I want something docile and something that won't get too big (6 feet max), but will be bigger than my ball.
-I want something that likes to be handled more than my ball python.
-I like the big heads of the boas. There's just something about it that intrigues me.
-I will keep it in a tub of whatever size the boa needs.
-I am good with keeping the humidity of my ball python, and she has a constant hot spot, but her ambient temps usually stay about 75-85, depending on if the heater is on her. So I need something that can bare a bit of temperature gradient. Or something that doesn't require high temps. That would be even better. If not, I can accommodate to its needs.
-I will probably get a male.
-Not very interested in getting a morph.
-Relatively low prices would be nice.

I have thought about a Dumerils Boa, a Leopard Boa, a Brazilian Rainbow Boa, and a Hog Island Boa.