For soda, which is much more highly carbed than beer, you need very long serving lines to balance the system.
I used 30 feet of 3/16" line, and that worked out really well for cold (fridge temp) soda at 25 psi (or 30 psi- I can't remember now). I haven't done soda in the keg since my last child left home, and now he's over 21 so he drinks a beer when he stops over.
Broken Leg Brewery
Giving beer a leg to stand on since 2006