I'm exporting a 75-minute narrative film from Premiere Pro CC 2015, shot on GH4 4K internal codec (4:2:0) and edited in a 3840x2160 24p sequence. I'm on a late 2013 Mac Book Pro with NVIDIA GeForce GT 750M.
My final output is 1080, so I'm thinking of the following steps. Would anyone like to chime in as to whether this seems right?
1) Render previews to 1080p ProRes 4444 w/ "Maximum Render Quality" checked. I know this isn't strictly necessary. But given the length of the project, I figure I will have to review the exported version and make tweaks. This keeps me from spending hours and hours of exporting with each revision. I only dimly understand how it works, but downres-into 1080 w/ the 4444 option will give me better color space, right? Every shot in the sequence will have at least Lumetri Color filter applied; some shots will also have Colorista III and/or MB Looks applied. It's not "heavy" color correction, just moderate tweaking.
2) Export to 1080p ProRes 4444 with "Use Previews" checked. I think this should go fairly quickly because it is basically just stringing together the Preview files.
Mac Book Pro (Yosemite)
2.6 GHz Intel Core i7
Adobe Creative Suite CC2015
Magic Bullet Suite 12