Honda GX35 fuel return line on aftermarket tank

I'm putting together a new bike using a Honda GX35. The stock fuel tank is much too small for my taste, so I'm taking it off and replacing it with a 1-gallon aftermarket tank. The problem is that the tank will be mounted quite a bit higher than the engine. The fuel line is no problem since the tank has a petcock on the bottom. But the top of the tank may be about 14" above the carb. Do I really need to run the fuel return line all the way back up to the top of the tank and drill a hole for it or can I do without it?

So just drill a hole of the right diameter at the top of the tank and push the return line through, or do I need some kind of grommet? Does the tank cap need to be vented or sealed?