Ah that's helpful thank you! Presumably as most people are saying all new 457 visa applications will be processed with the new two and four year options.
I'm just struggling to get my head round with any occupation on the STSOL list any way you could stay longer! Also if 1 or 2 years on a 417 working holiday visa would count towards the 3 years now needed to apply for PR. But maybe it will become clearer in a few months!