Consistent output with Image Generation Field Agent

Does anyone have a trick for generating consistent images with a field agent? I have a few collections that need to follow a template. Eg. Headshots on the same gradient background. What tends to work is what feels like a big bandaid: creating a table of ‘reference images’ and linking all the records in the collection to a template in the Reference table, looking up the file, and mapping it into the collection image field agent prompt. 

I have another collection where Im generating claymation style images, no template, but the output has drifted over time. I haven’t changed my configuration. Before I do the reference table setup, I wanted to see if anyone has a better solve.