Workflows like this are used all the time these days, but the F5 & F55 make it particularly easy. For an in-depth look at this workflow in action, watch my two videos - in the first part above, I explain how to set up the camera for simultaneous recording, including how to add a LUT to the HD recording, and in the second video below, I complete the online/offline workflow, showing how to take a basic HD edit and match it back to the 4K RAW content.
If you want to learn more about the F5 & F55, make sure to keep your eye out for our Sony F5/F55 Intensive workshops!
Update: With the release of version 1.2 of the F5 & F55 Firmware clips can now be named in the camera and those names can be synced with the R5.