> I do wish there was a better way to describe 'not convicted'
> other than 'innocent'.

I am no lawyer, but "innocent" seems to me to be a strict subset of "not guilty". Civil cases are judged on the balance of probability, but in criminal cases the expression "beyond reasonable doubt" finds much use. This leaves room for the Scots verdict "not proven" (often translated as "not guilty, but don't do it again").

Again, IANAL.