To test different stove ideas (or fuel) and to make design decisions, you need to have control of all of the variables. Here is a simple test: repeat the test, say six times with all the factors the same (water temp, air temp, amount of fuel and zero wind conditions) and compare the results. If the time to boil has a lot of range, then you do not have all of your variables under control. I would imagine that the total range would be well within 20% so a 60 minute burn would be +/- 6 minutes. The biggest variable that I have found is wind. Wind will increase your burn rate and reduce your coupling efficiency between the stove and the pot.
Once you have control of your variables and are getting consistent results, you can compare two design ideas. An ideal way would be to perform a T-test for significance. Best regards - Jon