Read this Apple White paper:
https://www.apple.com/final-cut-pro/docs/RED_Workflows_with_Final_Cut_Pro_X.pdf
Install RED plug-in for FCPX:
https://www.red.com/downloads/options?itemInternalId=16135
While you're at it, install RED CineX:
https://www.red.com/downloads/options?itemInternalId=16144
Keep the media external to FCP Libray: Library Properties/Storage Location/Modify Settings/Media/ Choose a Folder on your HD. All Media Links/Optimized Media and Proxy Media will live in this folder, making it easy to track at the Finder level.
Make sure to Import the RED clips without Transcoding them. In the Media Import Window, make sure Transcoding Create Optimize Media and Create Proxy media are turned OFF.
The operation can be done at a later time, after you have tweaked the RED RAW Settings in the Inspector. All Transcoded Media is deleted as soon as you modify the RED RAW Settings.
Selecting the Clip(s) will show a skimable, properly adjusted image in the Import Window.
After Import, Show the Inspector, and Show the Info. At the bottom you will see the "Modify RED RAW Settings Button. It automatically reads all Camera settings and adjust settings, but if you want to tweak the look, this is where the magic happens.
For smooth Playback, depending on your machine/hardware, make sure you are on Better Performance Playback settings, which plays at 1/4 resolution.
After you are happy with the RED RAW Settings, selects the clips and Transcode. Create Optimized Media will generate ProRes 4444 Full Res files, and these are quite large. Create Proxy Media will generate ProRes 422 Proxy Half Res files and these are small. Depending on the space you have available you will want to skip Creating Optimized Media and work on your edit exclusively in Proxy mode. Switch Playback Quality from Original (R3D) / Optimized (ProRes 4444) to Proxy (ProRes 422 proxy.)
With Proxy skimming and playback are super fast and snappy. The timeline is very responsive, and I'm on a classic Mac Pro.
Exporting 1min. of Proxy Timeline to ProRes Proxy takes about 45s on my old system. Exporting 1min. of R3D originals to ProRes 4444 takes about 5min. That's also the time needed to Transcode to Optimized ProRes 4444 if you choose to do that upfront. When exporting from an Optimized Prorez 4444 Timeline on the other end, the export time is cut in half, 2.5min. for 1min.
I edit with Proxy and I don't bother with Optimize Media. Especially when finishing in Resolve, there is no need. Now if I finish in FCP, then yes I must Transcode to Optimized ProRes 4444. I will only Transcode a locked cut Project, and only the clips used in the Project. That usually saves space, although FCP will Transcode the entire media, not just the I/O section of clip used in the Timeline.
