>I wonder how long it would take to get to 75WPM on graphite. A decade?

Assuming you can already type that fast, 3-6 months at most I would think (with daily practice / full immersion). My best speed with QWERTY was 160wpm and I was able to get to 120wpm+ with Dvorak and later Workman in under a year each. One big tip I have is to not avoid typing particular things. Enable the punctuation, symbols, numbers. You're gonna be slow at everything at first, so might as well train in a well-rounded way. A friend of mine chose not to do this and struggles greatly with typing numbers and symbols. monkeytype is my favorite site to train speed, but there are some others that are useful for the first few days as you're drilling where the keys are and getting used to typing common bigrams.