For soda, I just use those goofy picnic taps. I have to open the door to pour one, but then I don't have soda in my beerlines.
I use 3/16" line for soda- but 30' of it.
If you're having a dedicated tap just for soda, that's awesome and my advice won't really be very helpful, though!
Broken Leg Brewery
Giving beer a leg to stand on since 2006