I used
Elizabeth an a middle name for family reasons. I wouldn't use it as a first name because
Elizabeth is so much more beautiful than its short forms that I'd rather keep it that way.
I would happily use
Margaret as a fn; none of the
Margaret people I know has used a nn as an adult, and most aren't too bad anyway.
Margaret Lucy JaneMargaret GeorginaMargaret RuthMargaret Alison