How do we archive in lower res ?

Hi

We record a lot of footage in 4-6K and mostly, it ends up as 1080p at the clients. We just like to shoot in higher res for better cropping, zooming etc.

When a project is done, we'd like to be able to convert all the original footage into 1080p and relinks the files as it would A ) be completely fine for us to "only" have a full HD backup as we almost never changes anything to an existing project and B ) it would save a LOT of space in our archives. Especially as we shoot RED raw.

What would you guys suggest as the easiest way to do this?

Should we run all the files through compressor and just overwrite the existing files - will FCPx then automatically use those versions........ or are there better ways of doing this?

One of our freelance people actually said "Just transcode optimised versions within FCPX and dele the original footage - then you save the space and can still use the transcoded files if you need to"