I have wave petunias planted in most. a few are planted with marigolds.
I tried different ways of potting them, not that it's made that much of a difference. I took 2 out of their original pots, pulled some of the root apart and repotted them right back in their original container with a little extra soil, then I put the pot in the canvas bag. Two I potted directly to the bag with small drainage holes cut in the bottom of the bag. Two I potted to the canvas bag without cut drainage holes. Two I repotted to a small baggie with cut holes at the bottom for drainage and then I put that in the canvas bag.
My friends like the look, but they are a pain to water. Too many small pots to try to take care of.