Adding External Light Source Data to Metadata

What problem do you see this solving?
Do not see an a IPTC field for this option. And wondered if there was a way to implement this into its own category. 
Certain clients request an extensive metadata list. And I realize this info can be placed into a separate  excel spreadsheet, but wondered for more fluid consolidation of a readable EXIF files that could be shared in camera would be better?

When was the last time you were affected by this lack of functionality, or specific tool?
Often and have implemented Excel options for this. 

Are you using any workarounds or other solutions to achieve your goals in Capture One?

Currently added the light specs into the Keywords function, but  still wondered if there is another way to do this in a IPTC field?

Are you happy to be contacted further about this suggestion or request?

Yes