Australia and South Africe went for 10 shillings as the datum for the new Dollar or Rand. It was easy, really, as all the existing coins but the penny were a decimal ranging from 5% to 25%. It also got them out of the Sterling Area so they were in control of their own currency.
Interesting, considering that today's tourist exchange rate for £1 is $A1.86 and RSA18.6 with the former exceeding the latter by a factor of 10.
Jack