I concur on Carpet Python. Some get big, but several species stay small.
Irina Jaya's (IJ's) stay small as do Darwin's.
Yafe, is a mix of both. He shouldn't be longer than about 5-6 feet and probably will be noticeably less thick than a Ball Python. Being a male, 5ft is probably more reasonable. I was told by multiple people that a IJ/Darwin mix could live it's whole life happily in a 3X2' tank. However, they need height as they like to climb and love perches.
My Boaphile for him is a 4X2X1.5' with 2 perches (2") running from side to side on the tank. He went on a 4X2' tower so I gave him a little extra room. He does use the room and spend 75% of his time out and about as a display snake. At night he's all over the tank and during the day, he's usually on his warm perch.
Darwin's are know as the most arboreal carpet and IJ's the least. He's pretty arboreal, but will spend time in his hides.
Of note, Darwin's are more expensive. Both are known to be more docile/placid species even as young ones. However, Carpet's are known to be bitey when young. Yafe hasn't nailed me yet, but likes to his, especially when I try to get him off his perch!
I've heard 90% of them grow out of it.
Yafe loves to wrap around my arm and chill, but is more active than a boa by a little bit, I'd say. That doesn't mean he doesn't like to chill, but when he moves, he tends to move faster and a little less relaxed than my two boas.
Yafe's thread is below, if you want to see what he's about. You can skip more towards the back, as the beginning has a lot of drama. He was very sick when I got him.
I have heard that Carpet's are not as hardy as Boas, but get a captive bred individual, and meet husbandry requirements, and you should be fine. I don't think they are any worse than a BP, but Boas are pretty tough, especially BCI.
https://ball-pythons.net/forums/show...ression-Thread