Antec 900 - PSU Fan Question

This post didn't get any takers in "General Homebuilt"; here's hoping you guys are up to the task.

Ok, this is tricky. The Antec 900 has a 200mm fan on the very top of the case that sucks hot air up and out. Also, the 900 puts the PSU at the bottom of the case. PSU fans typically suck in warm air from inside the system, through the guts of the PSU, and finally blow this now-hot air out the back, outside of the case, right? My questions:

1. With the PSU installed in bottom of the Antec 900, wouldn't it make sense to reverse the PSU fan direction, so it sucks in cool air from outside the case, and exhaust the (slightly) wamer air into the case, where it would then be sucked out by the top 200mm fan? This seems like it would make a smoother airflow pattern, and increase the overall CFMs of air moving through the case.

2. Which PSU style would be better - fan out the back end, or fan on top (bottom, but PSU would be mounted upside-down in the 900 case)?

Thanks!

Altazi