Dumeril's boas do really make wonderful pets, my girl is about 6 feet long and is an overall big sweetheart.

Dumeril's are very docile, calm, sweet, and very very beautiful. They are my favorite species of snake and do really make awesome pets for a semi-large snake. My girl is only 13lbs, and not really hard to handle. I would assume a 20lb Dumeril's would be one huge female.

I would consider getting a baby to start out with and watch it grow. They take some time to grow their big size, but it's always nice starting with a baby to get it used to you and having that same baby, but as a very big baby LOL.

Carpet pythons get a nice size as adults and do make pretty good pets. As babies, most can be nippy, but some eventually grow out of it with or without handling.

I plan on getting a JCP soon, since I love their adult size and beautiful coloration. I've held probably two carpet pythons in my life, and Irian Jaya and a Jaguar (held the Jag yesterday!), and they aren't too bad with handling. The Irian Jaya wasn't used to it and it was a good 4-5 feet LOL, I didn't get nailed though.

SD Retics I don't have much experience with, but from what I've heard they are just like normal Retics, just come in a very small package. They are pretty cool though, and I'm sure with any snake if you handle them enough they will become a great pet.

Have you ever considered getting a Boa constrictor (BCI)? They make awesome pets and my boy cracks me up all the time because he's just very different from any snake I've owned. They are a very docile species and are a good first semi-large pet to get into.

I'm all in for Dumeril's, and they seem to be becoming a much more popular snake. They do make awesome pets so I would totally suggest one. Their only downside is finicky eating, but you can get them out of that with time and patience. Whatever you choose, good luck with it