I like the copper/nickel lines, like the type that's used for brake and fuel lines. It's easier to bend than steel, and slightly more rigid than copper. Some people like to put a 360 degree "vibration loop" in both lines. Use 1/4" diameter tubing with either flare or compression fittings for a bypass filter, or 1/2" for a full flow.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!