What octane do you guys run in your 2 strokes?

I have always ran 87 in my 2 strokes with a 32:1 ratio. I recently got a new Husky saw and I was reading the manual and it said to use a minimum of 89. So far I have ran it about 3 hours with 87 and a 40:1 mix of Husqvarna synthetic oil. Also think it said not to run it with more than 10% of that ethanol crap. Do you guys think I should switch it to 89 or keep it where its at at 87?I think that someone a while ago told me that with a higher octane, your air cooled engine will run cooler. That true? Not sure since I have already ran it for a little while on 87...