I would reccomend just about anything you can take care of! From what I hear most GTP's are snappy. And red bloods are/can be very vocal. They are also picky about their humdity and temps. Though once you have those right, it's pretty easy from there.
my male(about 99%sure) red blood is about 3ft, VERY strong for a 3ft snake, and about as big around as a soda can (he is also a little over a year old).
So far his temperment has been awesome, only going to into "S" position once, and that was because I startled him!
His feeding is great, anything my bp's don't eat, he does (which besides how beautiful he is, is another reason I got him, he's my little garbage can! lol)
His feeding response is quite lazy (lays there with his jaw on the ground, opens up and waits for me to place the rats head in his mouth!) Though I have heard of some of them that go crazy the second they "smell" the food.
Just remember that Red bloods are mostly ambush predators and don't usually actively hunt their prey.
And just because they are fat looking, doesn't mean they are slow!
Pick what you like, study it, and if you feel you can handle it, get one!
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1.1 Ball Python, 0.1 motley amel corn, 1.0 western hognose, 1.0 red blood