Hi Jeff. How fun! I have never made that cake into cupcakes so I can't give you a definite time. My untested suggestion would be to fill the cupcake papers half full and bake for 12 minutes and then check them for doneness.
You may want to bake one cupcake off in this manner and see how high it rises as well as how long it takes.
Note that this cake recipe is a high ratio cake, so it has a fine, more dry crumb. It won't dome and rise as much as other cakes.
Let me know how it goes!
Tara Teaspoon
https://tarateaspoon.com/spice-cake-with-creamy-caramel-icing/