Nitro Gas Mix

I recently switched over from CO2 to Nitro/CO2 mix, because I'm running a stout faucet on one of my lines.

I only have room for one cylinder in my cooler, along with the two kegs. However, my other beer (currenlty an amber ale) is extremily foamy.

Will it help to increase the tube length between the keg and faucet on the second keg to reduce the foam, or am I wasting my time/money?

Increasing the line length by a factor of four would help. If you are currently running 10-12' of 3/16, you'd be looking at 40-50 feet. Not very practical and what would you do when you don't have a stout on tap? Switch out tanks and lines?

Realistically, you'll have to use both tanks and keep one outside the cooler.

I currently have a very short amount of line running from the keg to the faucet. When they local HBS set me up, I only ended up with about 4 feet... could this be my problem, and if so, is it worth trying 16 feet?

I plan on running a stout or cream ale primarily on that faucet. Further, I've had other beers on Nitro (usually in Portland) and they're very good... I wouldn't mind trying one or two of my own on Nitro, if I can figure out the correct solution.