I found this one very difficult and didn't know where to start for a long time. I used
@NicoleJohnson's app as inspiration and used a lot of her ideas for the first part of the macro, then finished it myself. I wanted to be able to put in a list of numbers (of boxes) and then it runs through them all and finds the right combination. It won't work if it goes above 9 at the moment, but I couldn't think of a good way to get all combinations of the numbers of boxes if one of the numbers is 10 or more.
Anyway, I learned a lot in the process so I'm glad I persevered!
Outside the batch macro
Inside of the batch macro