The 2nd ring was eliminated in very high revving engines because of drag.

This puts a lot of extra stress and wear on the top ring.

For low revving engines, 8,000 rpm and less, the 2nd ring adds power and longevity.

I also like to run Opti-2 oil at 75 to 1.
It's recommended at 100 to 1 but I have noticed extra power in my chainsaws at 75 to 1.
I'm guessing it's because on the better ring seal.