setting boundaries and moving forward with BPD sister

Hi. My sister displays many of the characteristics of BDP. After years of trying to help her (not very effectively) I am finally trying to set us on a new, kinder and more compassionate path. I sent an email that explained the impact her actions have on me, and told her I didn't want our relationship to continue on its current path. I provided a few examples and also told her she was very important to me and that I loved her. she responded in an unexpected way - she called, was very emotional but actually asked some questions. She tried gently pressing a few buttons (eg telling me she had considered self-harm and had a plan) but stopped when I didn't respond. She was genuinely (I think) shocked that she has had this impact on me for so long, and I acknowledged that I had handled things badly by not talking to her about it.

she lives interstate and I am flying to see her this weekend in hope we can start to set a new course. I have no idea what I'll be walking into. There's certainly no guarantee it won't be hostility, blame and 'well you've done this to me'.

Has anyone been down this road? I'd love some tips about how to manage what will be a very emotionally charged situation. i just want to have a good relationship - not one where I'm adored one minute and hated the next.