Wow!
Pablo has 3k posts of experience and his opinion on the mix ratio differs from mine... I think I'd surely take HIS advice.
I've been in a pinch, way back when, and sloshed 6ozs of 30wt into a gallon of high test to run something or other with a 2 smoke engine... it got the job done.
It's a new day !
The new synthetics are far superior products than anything we ever had in days gone by. Personally, I would not be concerned running ANYTHING at 40:1 and would probably slim it to 50:1 after some test runs.
100:1 Opti2 is enough to make me nervous, but quite a few very experienced fellows claim to have good luck with it.
Question that comes to mind is, if you wouldn't try it on a HT china girl engine, what would you be willing to try it on? lol
I'll do it when I run through the supply of assorted chainsaw and outboard motor oil I've got bangin' around here already. I just blended a bunch of short bottles and ran it today at 50:1 and beat my last best speed through the radar sign by 1 single mph ! (I gotta go yet another main jet size smaller to lean it out just a little more. It 4 strokes all over the rpm band, but has very good pull at lowest rpm, which I do like.)
Best
rc