Cycle magazine of February 1978 has a five page article on two stroke pre-mixes. I have it as a pdf, but don’t know how to ‘share’ same here. They test 15:1; 20:1; 30:1, and speak of 50:1.
Their ultimate sentence is, quote: –
“Less, in the context of pre-mix lubrication concentration isn’t more; it’s less. Just as logic always insisted.”
I have a family member who ran a Husqvarna 360 chain saw for twenty odd years on forestry work on the most frugal of mixes. He even used used car oil to lube the chain. I had the job of servicing his saw when it died, and found the cage of the main ball bearings disintegrated, the small parts finding their way above the piston where before being ejected through the exhaust port, had hammered the piston top so much that instead of being flat topped, it was dished! New bearings and piston later, it lived to see many more days of work.