You may need a larger than 1/2" feed pipe from the source to be able to run all 3 burners. I believe 1/2" may only be adequate to run 1 burner at a time, but I will let others with more experience chime in.
I am also exploring using NG instead of propane, and from the discussions I've had, it seems like your lines may be undersized for a full 3 burner setup, if you plan on running more than 1 at a time.
Kegged: Octoberfest Ale
Kegged: Gumballhead Clone
Kegged: Bee-Cave Haus Pale Ale
Ready to Keg: Milk Stout
On Deck: planning a Belgian Red Ale and another blonde ale for easy summer drinking.
Meads: BOMM, JAOM and Tart-Cherry Melomel aging.