I think fuel hose is preferred. If you do any deep water crossings, consider doing the "T" mod while you're in there.

 

 

 

You don't need the exact factory tube, of course, but make sure whatever vent or overflow hose you get from an automotive source that it is fuel or emission rated. If it isn't, it will turn hard as a brick in short order. Automotive emission hose is usually preferable for vent tubes over automotive fuel line. Fuel line has to be thicker and stronger as it's exposed to pressure. Emission lines have little to no appreciable pressure generally, as they only have to deal with fuel vapors. They're thinner and more flexible.

 

I used fuel line because it's all they had at Advanced Auto that fit this carb. It seems tough enough and blends aesthetically with my decor/color scheme...
(what beautiful carb venting! I love the continuity of your hose palette... can I buy you a drink?)... t