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: Umlaut my Kölsch VII #2: Empty
Secondary #1: Empty #2: Empty #3: Cab MerMarqeNac Wine
Kegged: Mugged a Monk Paters
Bottles: Dark Belgian Strong, Black Raspberry Rhubarb wine, RIS, Carmel Apple Cider, Big 50 Barleywine, Framboise Lambic, Barolo Wine, Berry Rhubarb Wine, Black Currant wine
On Deck: BGSA