I use 3/16" line with an 8 foot length served at 10 psi. The Perlick faucet is 1.5' above the top of the keg.
I also have a section of 1/2" copper, of which 3" is in the cold fridge to conduct the heat away from the warmer tower temps. Helps reduce the temperature change and reduces foaming on first pour (great tip from someone here)
Primary #1:Dunkel #2:Empty
Secondary #1: Peach Rhubarb Wine #2: Empty #3: Empty #4: Sparkling Elderflower Wine
Kegged: Umlaut my Kölsch V
Bottles: Big 50 Barleywine, Framboise Lambic, Dark Belgian Strong, Belgian Golden Strong, Kicked by a Moose Scotch Ale, Apfelwein, Russian Imperial Stout, Barolo Wine
On Deck: Irish Red, Surly Bender clone, Spruced Warmer, CDA