Very cool. This sounds much like my first half-year with my BCI. It was very frustrating at times, and there didn't seem to be as much progress as soon as I was expecting.
I started to wonder if I simply had an aggressive snake, and that I would have to deal with it. I made a post about it, and the next time I held him, he started being a lot nicer. Fast forward to now, which is about eight months after I got him, and I sometimes consider him sweet. He doesn't watch my every tiny move with suspicion, and so on. The only trick is that he is not at all confident in my hands or on me, unless I provide firm support to his tail. He freaks out pretty fast, but it's getting better as he gains weight.
It's a very interesting progression isn't it?