Tuna cans are far superior than soup cans for this purpose. It is a matter of height versus width. You almost have to work at tipping them over.

I have made and recommend both the tuna candle and the buddy buner. In fact I started making buddy burners over 40 years ago. Although the way I learned to make them was with newspaper rather than cardboard. One other nice thing is they can be refueled by simplely placing pieces of paraffin on top of them while they are burning.

The candle is the same process only you put one or more wicks in the can instead of the cardboard. With a tuna sized can this can be up to 5 wicks. The more wicks lit th more heat is generated for cooking. Also you do not have to light all the wicks every time.

The difference between the two is. The candle form genereates more usable light but less heat. While the burner style generates more heat the cardboard or paper acts as a single gigantic wick. But not nearly as much light. Either can operate as a candle or a heat source but each functions better for its own purpose.

Another nice thing about using a tuna can is that they sell plactic lids made to cover cat food cans for keeping open cans in the refer. These lids perfectly fit the tuna cans. As long as you let the can cool after use so as not to melt the lids they seal and cover the top to reduce the mess for storage.