When I’ve had problems like these (things I wanted to fix by hand which were too many and too distributed across the language), this is how I’ve handled it. 1) I’ve searched for some canonical list of $WORDS, where in this case they are the list of words pronounced differently in US and UK English at the word level, and 2) got a list of the 5,000 most-used words in the language overall, and 3) taken the intersection of these two lists. At that point you may have a short enough list, but relevant enough, to make it not too terrible of a job to change them manually. If it’s still too much you can reduce 5,000 to something smaller, or vice versa if you discover it isn’t as many common words as you thought.