Dave,
Hey, this thing uses so little fuel you could probably get by with 1/2A sized lines. I used the medium size Dubro product. I still think we could find a better fuel line for gas engines if we looked. All of the "yellow" lines tend to get soft with exposure to gas and require that you wrap the ends with fine wire to prevent leaks after some use. Nothing critical here just use the one that fits the fuel inlet fitting snuggly.
Jimnie