Thought I’d update this thread to note that the multireplace function now allows us to do this without creating as many variables.
I think the {s} and {es} variables may still be the most efficient way of handling most verbs (plus possibly the {ve} and {re} that Lynnea Glasser used)… but for the long tail of irregular ones, multireplace is probably simpler and clearer than creating a new variable for each one.
I’ve offered a suggestion over at the wiki on how it could be done. Happy to take suggestions for edits to the wiki!