We recently installed Grommet Panels with Roman Shades at a residence for the designer Satomi Yoshida-Katz. The Flat Roman Shades only cover the lower windows leaving the transem uncovered. We used short rods on either end with Grommet Panels.
On the window opposite, we used a long rod across the window with the same treatment.
The fabric “rolled” nicely as you can see in the photo below.