i run a fuel log on my 511ci making over 800 hp with no problems..also flip back and forth from gas to alcohol and back to gas..same plumbing..i run a magnafuel prostar 500 and a magnafuel 2 port regulator.....if it were mine i would go with what you have..the dual line would probably be the cheapest..
just my take.
Brian
__________________
Bjuice..
"I'M YOUR HUCKLEBERRY ! "