Laura, it sounds like you have come a long way in a short time with an adult, re-homed bird.
Lots of wonderful advice on this forum.
Sometimes my spouse ''tries too hard'' with one bird or another and that can put them on edge. I think I have finally got through to him that his emotions when he approaches them is received by the bird. In the past he was nipped by

Jasper ALOT (no blood, but a few welts). I told him it was his own fault. He finally knows when, where and how to approach or not.
Your SC sounds wonderful.