Which location are you taking the class? Carb levels for most domestic beers is around 2.5 vols except for Coors' products. They have 2.8 vols. and require two additional pounds of pressure.
If the six feet will comfortably reach, start with this at 14 PSIG (16 for Coors' products) @ 38 beer temp. If you are comfortable with the flow rate, leave the six feet intact. If you require a faster flow rate, simply trim back four inches at a time until satisfied.
You may need a combination of 3/16" and 1/4" if you need a longer run of six feet. If so, we can advise you later.
Scott Zuhse, Instructor
Micro Matic Dispense Institute