>Pretty sure the BIOS must be set to GPT.
That's where I'm confused and don't have enough knowledge. It's definitely the best partition type but I'm not sure if type has to match type, i.e. MBR in the BIOS, MBR disk designation, or if type matters at all. It doesn't seem to, I have a mixture of types at the moment and no errors or protests from the system. I'll read up.