I've heard that alcohol is a good way to get a snake that latches on to let go. I'm not sure if that'll help much with the constricting part, but I imagine if you could get the head off, you could lead the rest off. (All just guesses, though! As I've said before, I have zero experience with giant snakes!) I don't doubt for a second though that if one of these snakes wanted to kill you, it could without trying. I would guess a good way to deal with the constricting part is to try and prevent it from wrapping around you in the first place? These are all just guess/questions, though....

Honestly, keeping a weapon just in case doesn't sound like a bad idea. As much as it would suck to have to resort to that (I couldn't imagine having to kill one of my babies to save myself), if I HAD to do it to save myself, then I would.

I think it'd be best to get my balls first, then boas (to get used to larger snakes), then maybe get a dwarf. If I can handle a dwarf, depending on how that goes, I MAY get a mainland.
All that being said, I do have a long way to go. But it's never too early to ask questions and research, right?