My feeling exactly on the GPS. I have never tried a disposable lighter at high elevations, but it does make sense they won't work as well. Usually when I start a fire, I will put the carbons in "birds nest" and have a couple cottonballs handy. As soon as the carbon takes off, I throw in a couple cotton balls, and then the small tinder, etc.
As for making the carbons.
Find a shoe polish can, the kiwi brands are the best. Put a small, match diameter hole in the center. Cut up old jeans to fit inside the can. Place about 10 pieces of cotton in the can. Place the can, with the lid tight on an open camp stove outside. The cotton will get hot inside the tin, and burn off all the dies. When the smoke stops, and a flame comes out the top, plug the hole with the match you used to start the stove. When they cool, these are wonderful fire starters. One little spark is all it takes. Place that in a bird's nest, get a spark in the carbon, and blow on it until it lights, being careful not to burn yourself.
As for the bird nests
Use the normal manilla/hemp rope, if you can find it. Separate the rope, and boil it out to the bare fibers. It may take several times of changing water to get to where there is no more oil in the rope. Once the fibers are oil free, make them into little balls about the size of a golfball, and place in your pack.
With the carbons, birds nests, cottonballs, and a striker, you have a firestarter that will start a fire in the worst conditions possible.
Just in case, I also have some steel wool and a 9 volt battery in case the other way fails. I need a 9 volt for my dog tracking box. It only takes putting the steel wool to both contacts to get it hot. Place that in the birds nest and away you go.
I also have matches, but rarely use them because the wind always seems to be blowing where I am at, lol.
Hope this gives some more ideas,
Later,
Marcial