Rear brake lines

[CamInHead]

So, I buys the Goodridge S12 brakeline kit on ebay expecting it to be not the right kit and I wasn't surprised lol.
I can use the front lines with my Z32 front calipers, and the rear pair look like they'll do, so now I find myself needing aother pair of brakelines to replace the middle set ie; between suspension arm and chassis.

I'm happy enough to have a bash at makingthem up but question is what size braided line should be getting, 3/8s or 7/16s ?

edit:

actualy, maybe I should have Earl's do it for me.
Assuming I want to keep the short section of hardline on the rear suspension arms, the flexi would need to be 10x1mm female concave at either end right ?