Even though that's the way the numbers work out, I think 12 feet would be too much. I use 12 feet of 3/16 on my soda tap and that is pushing 30 psi. I'd try 8 feet, since the cobra tap pours a little differently from a standard tap.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk