For what its worth @kmartial and @LauraLincks we have not been able to use the Admin–>Maintenance–>Update Category Option Combinations option for several years now, due to the large number of COCs that we maintain. Our solution is a manual one that involves creating new CategoryOptionCombos every time we are adding new CategoryOptions. It’s a tedious process, to be sure, but is definitely possible. Looking at categoryOptionCombos that exist through the api (api/categoryOptionCombos), you can get, pull, and use this as a template to create others. Personally I get a single COC json, put it into excel, pull out the necessary Items (the categoryOption IDs attached to it, the name, the UID of the categoryOptionCombo itself) and the create crosswalk columns for what I’m going to be replacing it with.
I will say, another, vastly faster option is actually to recreate the categoryCombo, but creating a new categoryCombo with the same categories included. The system has always (no matter the number) done a good job doing the initial creation of categoryOptionCombos. If you don’t have any data stored at all, you could simply swap it out. If you do, you could still potentially use this new categoryCombo (basically, the categoryOptionCombos should = the number from the original. If not, you can triangulate which are missing from the new categoryOptionCombos, and then move them from the new CategoryCombo to the original, thereby “patching” whatever is missing)