2 SSD, 1 HDD Setup for 4K editing, which drive for what purpose?

Hello,

What would be the best config with these drives for good fast 4K editing (source is h264) and exporting?

Drives:

250gb m.2 ssd for OS

250gb SSD sata III ssd

2tb 7200rpm HDD

500gb 5200rpm HDD (old, i know, but i have it from a previous build)

So, I'm thinking of:

OS and programs on the m.2

Cache AND scratch on the second sdd

Media on the harddrive

I'm thinking that putting the media on the harddrive might be the best solution (though not ideal?) since the size might be an issue for the SSD when it's also used for scratch and cache (thus storing preview files on the ssd)? I also read that pulling the media from another drive is better?

Where should I export to? The Second SSD, or the Media drive? Or just export to the older slow drive which isn't doing much?

Also: where should I keep my project files? Also on the 2tb drive? Those aren't written to as much as the cache and scratch I guess?

Thanks in advance for all the help and tips!