Lots of ways to skin the cat. On the back to front lines, sounds like 3/8" supply would work with any of the ideas posted. Another question... why SS? Its pretty but has drawbacks. Its not possible to flare it for custom connections as you will likely need with common tools. $300+ high end tool needed. Even then, seal is iffy as the SS is hard and has problems conforming to the mating fitting. Also on steel vs hose, repop steel lines package very well. Around the rear wheel house, for example, no problem with steel. A challenge with hose.

The OE mild steel lines on my car lasted 40 years. My mild steel replacements should last that long at least on a 3 season car.

No surprise, I suggest 3/8" mild steel supply lines and 5/16" return.