You can also use 100 LL which is 100 octane low lead aircraft fuel
poisonous additives
Technically Avgas 100LL has poisonous additives, namely TEL. Even thought it is 'Low Lead' it still contains it, so i do hope you run these engines in a well ventilated place when using 100LL Gil. Plus i'm surprised you haven't had any issues with lead fouling the spark plugs on these engines when using that fuel.