Just an idea to help in the future. I use those small indicators for Lipo batteries on my Jerry can. When I have emptied the can I click the indicator to red and store it until I am ready to go and get it refilled. Then I add I litre of oil and click the indicator to green. Job done. No more worrying about the fuel mix. I add 19 litres of Kero and I have the correct mix.
John