Awwww, shucks. I am glad you have learned from Behira's thread, as have I. I've also learned from other users on here who have far more experience than I do.
BCI's seem a little more active than BP's, but not crazy active like many colubrids. Figment, my Hypo Lavender corn is very active. He doesn't' sit still for two seconds. However, he doesn't have a mean or defensive bone in his body. Totally docile, just active. My BP Shayna seems more active than many BP's I've seen, but that's not saying much. A little curious, but also somewhat shy. Solana the baby corn snake, is actually really calm for her age. She's less active when being handled than Figment, but again, neither have a mean or defensive side.
Behira can be active and want to go in X direction, but she takes redirection well, and once she explores for a few, is happy to chill. She is super brave and has virtually no fear. She lets me rub her head and chin, etc. Doesn't care. I don't make a habit of it, but it's interesting that nothing really seems to bother her. She's also the most inquisitive and seemingly has the most personality.
You've fed colubrids, so you know about a strong feeding response. Good. BCI's are known for having a very strong food response. I started hook training at 600G and should have done it sooner

. Behira has a similar strike response to Figment; she's on the prey fast. However, unlike Figment, she will get excited as soon as she thinks food is coming and nail the acrylic doors, etc. She also hits much harder than Figment did when they were the same weight. Now she weighs almost twice as much and is on her way to 13-15X his size.
Just think colubrid food response X 2 and with a very large snake.
Otherwise, BCI's are a breeze to handle. I got to hold a 5 year old female, a momma, at the last NH reptile expo. She was about 7,000G (15+ pounds) and about 7 FT. Gentle giant. Awesome experience. Really excited about Behira getting big now and not so scared.
Behira's dad was 5ft+ and her mom was over 7FT. I am expecting a big girl.
Anyway, we are here to help and I hope your experience with Cas continues to be positive and lasts a lifetime.
Keep us in the loop! He's so pretty and it's going to be awesome watching him grow!