Is FCP completely unable to scale clip attributes? For example, conform a 4K clip to a 720p proxy that had custom scaling and position applied.
From my tests changing the sequence settings or using Media Manager does nothing to these attributes. FCP's manual confirms that besides the severely-outdated OFRT, HD offlines should be kept at the final resolution.
Basically, we have DSLR-originated 4K material without the horsepower to edit at full rez. We have to offline at a much lower resolution, and I have several push-ins that will require the higher resolution.