Response to your questions .
He is 3 years old now a little over 10 feet long. The second I open his cage up he goes into defensive mode . Meaning he gets himself in strike position and hisses loud as he can. He does not "come after me " but he will not hesitate to strike if I get to close . I handle him and clean his cage like I do with any of my other large pythons , takes more time but he's still on the same rotation . Once he's out of the cage he becomes more hissy , he will strike if he's startled or if you even touch him wrong . The thing that really seemed to help him being minorly tolerant is being VERY slow and VERY controlled in the movement I use to handle him. I TRY to not force him into a movement or a position . I let him do what he wants on his terms with some exceptions .Generally resulting in a lot of hissing with a occasional freak out strike or two . The gentler I am with him the gentler he is with me. Sure it's a little more challenging but it also is something that I've accepted . A grumpy Burm is easier then a grumpy Retic in my opinion lol. Hope he settles down with regular handling . Sounds like there's hope . Hope that answers your questions at least a little bit . Good luck mate