Extra camp spaces for level 6 and above. In addition, Heroes TAKES up space in camp.
Th7s and Th8s should get 220 plus cc troops in total, while th9s should get 260 plus cc troops, then there are th10s with 280 spaces and th11s with 300 spaces (level 9 camps perhaps).
Each hero that are available to be used AUTOMATICALLY takes up 20 spaces in the camp. While they are being upgraded they free up spaces themselves for you to substitute them with any others troops you have.
Once a hero just finished upgrading it won't appear in your camp if your camp is full or nearly full.
This is my suggestion to help ensure your offensive capability isn't at a disadvantage when you are at least a hero down.