Questions about working with GH4 media in FCP7

[thetimecode]

I recently shot a music video with the GH4(in 4k) and GH2(1080) all the footage looks really good in preview playback but I notice a Gamma change with the .mov GH4 files if I open in FCP or VLC? I've had this problem with RED files and I just continued editing with the darkened gamma change because the files seem to correct themselves upon export. With that said I have a couple questions with how I should continue with this project or if there is a better way.

My workflow plan right now is to Transcode first all of AVCHD GH2 files with 5dToRGB to PRORES 422HQ

After that I'll import the PRORES files into FCP and drag a clip to the timeline and match the sequence settings to the clip because the final deliverable will be in 1080.

My question is with the 4k footage and if this workflow makes sense? Should I import the .mov files directly into the 1080 sequence? or should I transcode the .mov files to 4K PRORES? I know importing the .mov files will slow me down because I'll have to constantly render but I don't want to lose image quality in conversion.

My concern is the gamma will change and I wont know the true image quality until after I export. I just want to keep the images looking like they are.

What would be some of your workflows when working with the same type media?