Old Fart, the tanks we make up for most O/T models will hold about 50 to 60 mls. Allows for extra fuel needed if you are running a Duration engine. We were adding 30mls at a time after intially filling the tank to capacity. Corrosion was the death of the tank after at least 10years of use.
Question have you seen the new OS engines (petrol) powered by a glo plug not a spark plug. Called GGT engines. Interesting prospect, I don't have any spare cash otherwise I might have been interested. Now exploring the possibility of making our own rings to replace worn out ones. Found an article on doing it on the national Control Line newsletter from the 80's. The material used is Mennonite 4 which I can get from Blackmores. Just got to find a good 500degree heat source for annealing (and warming up the w/shop