Marc,
Getting back to your last comment, I am looking to output a file-size efficient format, with enough tonal range both in brightness levels and color breath in FCP to compress down from.
When you say "output a file-size efficient format", do you mean what you captured/recorded on the camera?
From what I can tell from the camera recording specs (I don't see anything HDR in the specs but the overview info says something about HDR PQ), for SDR you can choose from H.265/HEVC 4:2:2 10-Bit, H.264 4:2:0 8-Bit or Raw 12-Bit internally, and 4:2:2 10-Bit via HDMI. In lieu of choosing the better formats (Raw or HDMI out), H.265/HEVC 4:2:2 10-Bit seems like the best choice for recordings, if small file sizes are required.
For HDR, you only have one choice, "HDR PQ". I don't know what the bit depth of that format is (I'm guessing 10-Bit) or the color subsampling (4:2:0 or 4:2:2?). Is the "HDR PQ" recorded as HEVC or H.264?
I don't know what you mean about "enough tonal range..." FCP can utilize pretty much whatever you can give it, depending on how you set up and use FCP.
So gathering your comments, to get the broadest color space (wide gamut) in camera I should use the Rec2020 setting and the broadest tonal range (HDR) I should set the camera to record "HDR PQ", and set up my workflow as such in FCP?
Other than recording in RAW or via HDMI, I guess this would be okay.
I always tend to use a "Wide Gamut HDR" Library for all of my projects, regardless of color space, in which things were recorded, or if material was shot in "HDR". The "Wide Gamut HDR" nomenclature is somewhat misleading, in that you don't need to have HDR for wide gamut media, and HDR media could be limited to Rec. 709 colors. I haven't found any completely clear explanation of this stuff in any Apple documentation (they used to have excellent documentation in v. 1 through 7 of FCP). It's rather opaque, too much so, for a "pro" application (especially when compared with other NLEs).
So, use a "Wide Gamut HDR" Library, then choose your Project/timeline according to how the output should be (Rec. 709 or Rec. 2020, with HDR or SDR).
Basically my footage up until now (CLOG+Rec709) will not be suitable to be turned into HDR + Wide Gamut color clips in 10-bit 4.2.2 exports? I should treat them as Rec709 8-bit 4.2.0 files for output?
The output from FCP is based on the codec you choose on export (and limited by the color space and other settings for a given Project/timeline).
The recording format is the limiting factor. Depending on how you set up and use FCP, it may be useful to have the highest quality SDR footage, especially if you're going to do a lot of color grading/correction.
Your above statement is somewhat ambiguous. You can't really turn SDR footage into HDR footage. You might be able to "stretch" the levels of SDR footage to a point.
The reason for the confusion I guess is that I was treating CLOG sort of like a Raw format, where the flat nature of the file meant I could go for the broadest dynamic range and color gamut processing in FCP.
This stuff is confusing, at times, even when you know or understand most of it. Log gamma used in recording is useful, but it isn't the panacea it's made out to be by the camera and gear manufacturers. CLog (gamma setting) affects perceived dynamic range by sampling more levels from shadows and highlights at the detriment of mid-tones (it's a trade-off). The absolute range of levels (0 to 100 IRE for SDR footage, plus or minus up to 10, depending on the camera) isn't changed by recording using a log gamma, so saying (as many people do) that the dynamic range is greater when shooting log gamma isn't technically correct or precise. Better control of lighting and scene/shot construction is what the focus should be on when recording footage.
The color processing pipeline/workflow in FCP is a bit ambiguous. I'll leave things brief by saying that if you apply a technical (color space conversion) LUT in the camera LUT part of the FCP interface, further processing is constrained by that (making things "display-referred"). If you don't apply any LUTs (do all correction manually) or only apply a technical LUT (and optionally, one or more creative/artist/"looks" LUTs) at the end of the processing chain (at the bottom of the list of effects in the FCP inspector) you maintain the wider gamut from the recording (in which case this would be called "scene-referred"). This stuff is pretty clear in DaVinci Resolve, but it is a "black box" in FCP (at least in terms of documentation, i.e., the lack thereof).
Testing a complete workflow is the best way to sort things and ensure you get the best results. Learning to use scopes is good, as well. This should be enough to confuse you further or get you into trouble... ;-)
Cheers.