Not an expert here, and usually rely on other's with experience. I had been using Omega 15% in my 61SF's. I use ProPattern 20% in the YS110 & 115. I decided to try the 20% in the SF's, to just keep one type of fuel for both.

First time the 20% in the 61SF's, excellent run all around. I did not tach it, but can only say, pulling down to idle, and transition, best yet with the 20%, IMO, better then 15%.

Crank