The picture is how I do mine, keeps the carb from dripping when you fuel up. There are some rubber grommets at Lowes, Home Depot, that the fuel tubing fits snug into, on my latest I just ran the tubing those outside the fuse and joined it with a piece of Aluminum tubing. MK also makes some angled bulkhead fittings that work nice. Put your filter between the engine and the fitting closest to the nose, so you arent filling the tank through the filter.

I wouldnt hook it up to muffler pressure, doesnt need it, might just cause problems.

Oh and I think you can put a check valve on the vent, just so it lets air into the tank, it might stop the drips out the vent when the nose is pointed down when carried.

Hope that helps.