To me the 90 degree spine issue is kind of "meh". It's nice to strike a firesteel but most of the 'steels I carry have dedicated strikers (my favorite being the GobSpark Armageddon by Firesteel.com). Perhaps the bigger reason for that feature is to scrape wood to make very fine tinder. Great if you do it that way but that's not my usual technique.
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“You can tell whether a man is clever by his answers. You can tell whether a man is wise by his questions.” Naguib Mahfouz