Thank you so much! Your suggestions were super helpful! Turns out, I got the daylight shelves into my model through a combination of code in SU's Ruby Console and steps in the OS GUI. In case anyone else needs daylight shelves, this is how I did it:

1. Ruby console code (as per Avi's comments) above) to add the light shelf objects to the model and to create the light shelf construction; (after this step, the light shelves are not yet visible in the model)

2. Then, in the SU plugin, I drew the interior partition surfaces in the positions I wanted them;

3. In the OS App, under the Space tab's SubSurface sub-tab for Daylight Shelves, I dropped the interior partition onto my Subsurface's Inside Shelf Name field.

4. Then in the OS App's Constructions tab, I selected the Interior Partition construction and dropped my chosen light-shelf material (with relevant properties, etc.) onto the interior partition construction.

Ready and set to go for a simulation run to generate some daylight coefficient maps to check out illuminance values in my space, with and without the daylight shelves! Exciting stuff! :) Thanks so much!