Hi Daniel, to answer your question, Portra 400 should be good for magazine prints if you get high quality scans from a good lab. If I was you I would get the highest scan resolution possible (4492×6774) Works very well for advertising, giant prints and large posters.
I shot the image below on my Canon Elan7 with expired (2003) Fujichrome Sensia. BUT you have to understand the concerns from other's replies. Have you tested the new camera? You have to ensure there are no light leaks, shutter works etc etc.