1. What colors are available?
2. What are the measurements?
3. Does this help for tailbone or lower back surgery?
4. Will it support larger people?
5. Do you need additional back support for long road trips?
6. How hard is high density memory foam?
7. How thick is the cushion?
8. What is the correct way to use this seat cushion?
9. Does it get hot?
10. Does this work with a lumbar pillow?