I am planning to do something similar next season. Are you using specific flowers or anything you have on hand that has a low growing profile? And how long do you wait before seeding them (the time between tomatoes transplant and the seeding of the flower)?
I have tried some cash crop at the base of the tomatoes and cucumbers (lettuce, green onions, beets) and it works well for us. I did that early in the season inside the greenhouse. Once the same plant outsides came to maturity I just let the one inside grow and they was kind of a “cover crop” but it wasn’t nearly as full as it is in your pictures.