After some fiddling about I worked out that proxy files are good. I also worked out they’re better if you make them quite low resolution and tell Resolve to store them on your machine.
The idea is you put your real videos on the LAN, then generate proxy videos from them on your local machine. The proxy videos can be copied to other machines used for editing too. This can take a bit, but it’s a one-off task done inside Resolve. No weird ffmpeg scripts or anything.
Then when the video is done, you can render the real video acros your network, which will be a bit slow, but that doesn’t matter because it’ll render by itself.
I also learnt less compressed video files are better for editing from. So when I get the full-fat Resolve Studio I might experiment with making proxy files from the H.264 videos directly. Currently I have to convert those to MOV so the Linux version of Resolve can edit the video, because licence issues.
