hello,
Nukeyfox you may have answered your own thread there bro.. a good sharp blade for starters give it a strop, change the type of wood your using & the pieces that break off if they're thin enough direct the shower of sparks onto a bundle of these, see if these ignite. Just a thought.. is the wood tinder dry your trying to ignite? You say that you constantly produce notches on the branch when stroking which prevents you from making nice long curls, maybe your pressing too hard into the branch with your blade & being blunt won't help either. Perseverance is they key word stay positive & keep at it. BTW what kind of ferro rod (fire steel) are you using?
Regards
David