Re: The trick, I think is
No, the trick is that if you repeat statements other people have made, based on their work, I would have started asking you about those pesky details of the physics.
Since you didn't, I'll just comment that I have done similar work myself, and found it very difficult to sustain that thick atmosphere against self-collapse by CO2 condensation.
There is quite a bit of discussion going round on this issue and we don't have a final answer yet...