All good points and suggestions. 
Thank yee kindly. *blush*
I finally managed to teach myself to strike sparks into a tinder box last year. Holding the tinder on top of the flint and striking down with the steel is pretty easy. But it took a good bit of practice for me to get the stationary steel and moving flint thing sorted out. I haven't tried that method in a while so I could use more practice.
I too have found striking down into a tin to be slightly more difficult than holding char on top of the flint. Dunno if it is because we first learned the on top way and our mind wants us to get back into its comfort zone or what it could be. With practice can get as good of sparks but it does seem to take a little more practice to "throw down" (lol) than on top.
Most natural materials do not stay on top of the flint very well so being proficient at throwing sparks into a pile opens up a lot of materials for us to use.
I have found that there is something to having both pieces held in the air. When I pin the char with the steel, never get as good of sparks. Can't quite put my finger on why.
Have you tried holding the steel (either one really) at a 45 degree angle above the char? Most show holding the steel vertically (90 degrees) above the char. With the vertical hold it seemed like the only choices were poor sparks or scatter the char. This year I have been playing with tilting the steel from parallel (0 degree angle) above the char to 45 degrees away from me. After a couple of practice strikes we can adjust for where the sparks are falling and get just as many landing on the char. As with golf, a good follow through makes for a better swing. The big advantage to the 0-45 degree hold is the hand with the flint is much more likely to pass by the char without scattering it.
Each method has its advantages.
Absolutely. That's why I like to throw thoughts out there. Never know when we might want to try a different way just to shake things up. Or what innovation it may spark.
As for charring, I haven't had much luck with the scorch and snuff method as applied to cotton and brass tinder tubes.
Interesting. I tried it with three different sets (different diameters, compositions, etc) of ropes and tubes. All worked well. I found that there is often a fine powder on the charred end that catches the sparks super well. It can get knocked off with rough handling. Still work without, just not nearly as well. All in all, not a bad method but not one I would bet the farm on either.
If I could find some KNO3 I could probably treat the cotton rope to make it more like a matchlock slow match, which would work much better.
Uh oh, here come the singed eyebrows pics! Lol.
I found that the best charred cloth comes from batches that have a little bit of brown, undercooked fabric in them. You can remove the undercooked stuff and save it for the next batch. This gets the best char without overcooking it.
Yepper. A lil under charred in the center is a good sign. With most chars, while the under charred portion will not catch sparks, it will grow the ember (think tinder tube). More slowly than when properly charred, yet still useful. And as you mentioned, it can always be charred more later.
Primo charred cloth will leave little soot on our fingers, tears with an audible ripping sound, will catch the least of sparks then rapidly grow the ember.
When charcloth is super sooty/dusty, fragile, falls apart, or worst of all has white ash on it, it can be super stubborn about not catching a spark, if it will at all. Once any material has been over charred, there is nothing we can do to fix it.
Overcooked char doesn't hold a spark as long. The stuff in the video was overcooked a bit but it still worked.
Noticed that. Think you said you cooked it about an hour. Maybe 45 min would work better. Wonder if cooling it down more quickly (set the cup in snow or cold water) would be advantageous?
