I think you have done very well.
You are correct that matching thread to quilt color hides a multitude of "sins" ... and, also, if you use busy fabric, the quilting isn't so noticeable either ...
having said that, I have to share what my non-quilting daughter in law told me.
(I am trying to use up some white quilting thread I don't like, and it is taking a very long time.)
While the white sort of disappears on the front, the back of her quilt is a deep blue - - can we say "glaring"???
She really likes the back of the quilt the best. Every time she mentions that quilt, or any of the other quilts I have made, she mentions how neat it is to see how the quilt is held together.
I just thought you might like to know that you don't have to match thread and fabric <g> <wave>