Just a note: sometimes it makes sense to "make offline" the camera original and relink to the proxies. This allows you to export for client review much more quickly. When you're ready to finish, just reverse the process. I spent a week trying to make proxies that would work for material shot on the sony fx7 which has 8 audio tracks embedded in the file in some proprietary fashion. Finally just did the make offline and linked to the proxies which worked fine if not as elegantly as the official proxy workflow.