Using a direct draw system there are several considerations including the static pressure of the beer or the vertical lift (height of the tap from the center of the keg).
For example...if your tap is 5ft above the center of your keg.
Static resistance from gravity = 5ft x 0.5 pounds/foot = 2.5 pounds
Applied pressure of 14.5 psi must be balanced by total system resistance. Since static resistance equals
2.5 psi, a total of 12 pounds of system resistance will be needed: Restriction = 14.5 – 2.5 = 12 pounds
To achieve this: 4 feet of 3/16” beer line (choker) @ 3 pounds per foot would give the right pressure balance of 12 pounds, but would be a shorter run than the 5 feet represented by elevation gain to the tap. So you could use a combination of larger diameter vinyl, followed by a shorter length of choker: 3.5 feet of 1/4” vinyl @ 0.85 pounds per foot = 3 pounds resistance
3 feet of 3/16” vinyl @ 3.0 pounds per foot = 9 pounds resistance
3 + 9 = 12 pounds of system resistance.
In my personal experience, I have found that 6ft of 3/16" beerline with a vertical lift of 2ft works best at 12psi and 38F
Check out this excellent draught beer qaulity manual.https://files.pbworks.com/download/eLmYoGyKNd/draftquality/47312934/DQM%20Full%20Final%20V2.pdf