FCPx exporting 1080p from 4K Timeline - Mastering Audio/Video

Hello All,

I have 4K clips (24p) that I imported into a 4K timeline, after reframing and editing, I’d like to export as 422HQ file in 1080p. What is the best way to do this… 1) “Modify project setting” in the existing 4K timeline to 1080p, or 2) Create a new 1080 Timeline and Copy-&-Paste the 4K edit into this new 1080 timeline?

I’d like the final product to have the highest resolution, I shot in 4K, so could do significant reframing, for a final 1080 export. Will either of these two option have an impact on the resolution/quality for the final export?

Many thanks in advance, and sorry if this has already been addressed somewhere in the forums.

Steve