Favor endive and escarole as your staples and then mix in lots of variety.
The problem with grocery store greens is threefold:
1. They lack the fiber that weeds and leaves have.
2. Low calcium when compared to weeds and leaves.
3. Wrong calcium to phosphorous ratio in some cases.
If you are going to feed a lot of grocery store foods, you need to "amend" the food by adding fiber and using calcium supplementation. Add fiber by mixing in grass hay, grass, herbal hay, or ZooMed Grassland Tortoise Chow. Any of these will need to be introduced slowly and mixed in to the day's greens in very small amounts at first. It will take time for the tortoise to get used to the new taste, smells and textures.