What size of brake lines should I use?

[68fishbowl]

I just finished up my 4 wheel disk brake setup, and I was wondering what size brake lines I should be running. I have 5.5" Chevy calipers on the back, and a '74 Duster setup on the front. I was also wondering what size of proportioning valve I should use, as well as which reservoir. Stock? Thanks in advance.
Cris