First, thank you for being willing to cater to the very small customer base that this product is designed for. Those who use hexamine fuel tablet has always been small, but with the help of guys like you and others out there, we are helping to push forward some of the safety aspects of using hexamine fuel tablet when compared to alcohol for fuel.
I have a bit over 60 burns using the FF14 at this point.
Except for on the first day that I acquired it, I have used 4g esbits exclusively. I did use one 14g on the day I got it, just to test it out, but I am a 4g esbit user.
Using two different 400ml pot setups I find it takes:
6 grams to reach shrimp eyes - about 70-80 °C (155–175 °F)
8 grams to reach crab eyes - about 80 °C (175 °F)
10 grams to reach full boil - 100°C (212 °F)
I do not time how long it takes... that is for those who care more about things than I do.
I do not know how cold the water is... what kind of a hiker carries around a thermometer and sticks it in the water before they heat it up.
All of my testing has been done at elevations below 100 feet.
I have gone through about 1000 of the 4g esbits over the course of the 2013 hiking season and without using the FF14 I would say it is saving about 2 or 3 grams of esbit per heating, over not using it.
I am not really sure how consequential that is for the average hiker. For myself, at the amount of days I have done this year, and with about 1000 cubes burned through, and an average of it saving 3 grams per burn, if my math is right (which it usually is not) that would be a year-long saving of about 3000 grams / 105 ounces / 6.5 pounds - over the course of the year.
At this point in time I would have three recommendations for it:
1) The little triangle where the clip goes into should be a square, the triangle causes it to either not stay in there or to come apart when it heats up.
2) Consider making a two piece version. The design makes it a very odd shape and difficult to find a good spot when using these 400ml pot setups that some of us do. Having it in two pieces would allow us to shove it down into different spots in our cup along with the rest of the stuff.
3) Try to resolve the heat flexing issues, that you and I have previously discussed, so that the FF14 remains flat and does not result in warping and lifting up of the edges and thereby allowing extra oxygen into the unit, and/or allowing flames to be released out the corners.
Again, thank you Jon for helping out those of us who are out there using hexamine fuel tablets as our source of heating water while on the trail.