I found that 4 heat tablets boiled 2 cups water in 5 minutes with lid on top of pan.
I found that 2 heat tablets boiled 2 cups water in a little over 6 minutes with lid on top of pan.
I tried boiling 4 cups of water with 4 heat tablets but it struggled with that and didn’t quite boil before the tablets died out. Temp of that water ended up at 160 degrees.
Seems 2 tablets and 2 cups of water about optimal use of the stove and fuel, then.
Testing Environment: slight wind blowing. No rain.
Heat tablets lasted about 8 minutes.
Hard to light the heat tablets in the wind. Once going, flames are large and will curve around the pot. It does leave quite a bit of smoky residue on the pot, but cleaned up with soap and water. Some smoky residue left on bottom of stove, as well, from vent holes there.
Not much odor, but use in a ventilated area undoubtedly best!