barry, that is awesome you have been able to get the pepsi stove to work with such little fuel and also in those temps. I tried and could only get a boil with just under a full ounce in optimal conditions. That was the best I could do. Because it was such a pain to make the stove compared to others I didn't play around much with jet hole sizes etc... Friends have purchased pepsi style stoves with similar results. As I said, awesome you figured it out!
Same with sub-zero temps, do you use HEET (methanol) by chance? I ask because it has a lower vaporization point than ethanol (which I use) and is difficult to light at 0*F without using a wick. The only way I could get it to work is to drop a match into the fuel cup and let the match itself act as a wick. Prewarming the alcohol (body heat) was the only other solution I could find.
One of the cool things about alcy stoves is the playing with them to optimize their performance. Canisters are cool but not as much fun for me.