I just removed the tank this week
No trouble with the grommet or the seatbelt.
I thought that it was almost empty, but it turned out that
it had more than 7 gallons still in it
Didn't have any problems with spilling it
One thing amazes me though, after emptying the tank
there is still a small amount of gasoline in the tank, but
whatever I do, it won't come out...
Cya,
Edmond