Sabre
Around here a cup is 250 ml so 4 cups is 1 liter.
Just to make sure, I have just boiled about 900ml of water using one of my thin titanium pots on my stove top using the highest setting. It took over 4 minutes to get a roaring boil. My pot is 4.5" wide. If you can do that with alcohol not only you have the best times I have seen but you are exceeding the theoretical maximum efficiency of alcohol. Well done !

BTW, I do have several commercially sold stoves and made many versions of the supercat and Pepsi type my self. With 1 oz of Ethanol I get to boil 2 cups between 4.5 and 8 minutes depending on the set up. The faster the boil the sooner I run out of fuel. In the end most of my combinations give me 1.5 to 2 minutes of roaring boil. I am at 10 m above sea level. That makes your versions about twice as efficient as mine......