[snazzypig]

Another fine adventure there Fetch! If you can afford to keep non ethanol gas in your new tank it won't rust out so quickly.

To add to James' tip, I first slide the filler hose over the filler neck and tighten the upper clamp securely. Then insert the neck up through the grommet. I like to spray rubbing alcohol on the parts which makes things slide in place easily and it leaves no residue. Vaseline or grease works too. Next, hang the lower clamp over the gas tank neck. Then block up or have someone raise the passenger side of the tank, and slide the tank over to meet the lower end of the hose. Lower the other end of the tank so that the neck rises to meet the lower hose. The hose should be as low as possible so you can access and tighten the lower clamp. If your spacing is good at the top, the filler neck will protrude the right amount.
I'm sure there are other good ways to do this job, this is just what works for me.

With all your little helpers ready to help Daddy, it should be a fun project!