After reading this link Which 2-cycle oil for Toro snow blower.
I went out and change to Opti-2. I was assured by the bloke at the mower and chainsaw shop that 100:1 is the correct mixture for ALL 2 CYCLE engines. He also said that 99% of all professional lawn keepers use this stuff and report amazing longevity of their equipment.
I remember years ago when I got my first edger and lawn mower I used this stuff and the edger is still going strong after 15 years.
Appears to be great in the Z80 too. Even with only 150km's on the clock.