Since I wanted global, not merely project-specific, auto-corrections, here’s how I’ve found to do it on my Mac (an added benefit is, since these auto-corrections are at the System level, they work in other text programs as well as Scrivener):
I find that it’s most efficient for me to get into a Grow-The-Shortcuts-List mode while practicing the rituals of tapdancing at the starting line—for me, that’s usually: going online and/or going phone-line (a.k.a. Avoidance-line).
Even if this auto-correcting twitch is merely another form of tapdancing, at least it keeps me in Scrivener, messing about with my own writing, rather than in the outside world’s cornucopia of tchotchkes.
And, to paraphrase Water Rat, "Believe me, my young friend, there is nothing—absolutely nothing—half so much worth doing as simply messing about in words”
Here’s how to do it:
Keep Scrivener Preferences at the auto-correct option so that when you invoke Preferences, using COMMAND—COMMA keys, you only have to position the cursor onto “system text preferences”, click, and you’re in position to create your chosen shortcut (say, “srct” for “shortcut”). After you’re done using Auto Correct, two COMMAND—W invocations clear the screen and leave it in place for the next time.
Choose a file then press the COMMAND-OPTION-CONTROL-J keys to invoke Inspector in its Keywords window. Then, read through the file and highlight each word you’ve used a shortcut for that has yet to be converted. Drag it to the Inspector column (anywhere in the column is sufficient—the highlighted word needn’t be “placed”). After culling the file and compiling a fine mess of busy-work for yourself, invoke Auto-Correct and have at it.