Buy a quart of Amsoil Saber and then pour 4 oz into old 6.4 oz bottles. They are marked in 1 oz increments on the side from the bottom up. That's what I do, and I have a bunch of them on hand all ready to go like that. I keep one in my tool box in case I'm out somewhere and run out of mixed fuel. rarely happens, but does once in a great while. 4 oz into 2.5 gallons and you're at 80:1. No fuss or muss. A quart will run you between $10.50 and $12 depending on where you get it. 6.4 oz and you're at the normal 50:1 if you feel the need to go that route. Go to Amsoil's site and do a dealer search. I bet money you have several near you that you don't even know about. Most are private individuals that sell right from their home.