You're never going to get the same atmosphere on Mars vs Earth. Not only are you going to need to make a lot of tradeoffs with respect to gas content (eg, that

You're never going to get the same atmosphere on Mars vs Earth. Not only are you going to need to make a lot of tradeoffs with respect to gas content (eg, that much nitrogen is going to be very difficult to find/relocate) but the same amount of atmospheric pressure is going to take a larger mass of atmosphere since there is less gravity. So it really is a hard question to answer since to answer it you'd need to know what kind of atmosphere Mars would have.