Okay.. Simple Question...

I actually just went through what you did when I installed my new grommet last week on my dusters tank. To top it off, the car has fresh paint and so did the filler tube so I was trying to be carefully of both of those things on top of it being tricky to get it inserted. Finally after 5 minutes or so of screwing around I smeared a little vasoline on the grommet and it all slid together like a charm!. Also, for the heck of it, I put a bead of weather strip adhesive in the channel of the grommet so I know it sealed well to the tank itself.