need help 68 rear brake lines and hose

[mild68]

I'm in the process of getting the rear drum brake lines set up. Truck is a 68. The rear differential is either a 71 or 72 , 5 lug axles. The flex hose that was on the 71 72rear end connects from 1/4" steel line and has a brass T that goes to each wheel cylinder that is a 1/4" line too. I'm confused as to what the steel line size along the axle tubes should be.
The wheel cylinders take a 3/16" steel line.
The new flex line for a 68 requires a brass weather Head of sorts.
How should I set this up?