I do not think that this would have a positive effect on the flow. Surface too uneven.
I noticed with a door of my car damaged by an accident, and i noticed with my bike as well:
That canopy will slow down the bike compared to full cabrio mode, while the smooth GFK-Canopies improve aerodynamics.
BTW: Your sketch reminds me to that one:
https://www.velomobilforum.de/forum/...76ef9b14e2c695
(no swing arm, suspension completely removed - that one has now been converted into an E-Bike)