Ultimately my understanding is to get speed improvements you need more than 2 drives in Raid… and whilst you are benefiting from having 2 drives in terms of a drive dying - I have Time Machine running (and now - it will be on full time instead of when I remembered to turn the Firewire box on)… so - probably not going to worry about raid.
Next will be a Mac Mini lower-bay SATA cable so I can pop the Samsung SSD into the 2012 mini… I’m thinking I’ll use the Samsung Evo as my main drive, and WD Green as a scratch for editing.