I've never had any problems with a fuel line being too long. I just finished putting together a Long Ez and because of where the fuel tank has to sit the vent and fuel lines are about 10"-12" long, running an OS 46 FX. I haven't noticed any problems with them that long. I like to have my fuel lines a bit long anyway. As you put on and take off the fuel lines the ends of them will split or open up, and if your line a tad bit long you can just trim back the bad area and not have to replace the entire fuel line.

Hope this helps

Ken