Fuel tank position

[bigorange1]

I just replaced a sending unit on my 1998 Stratos 295 PE, but now I can't seem to put the fuel tank back where it was before I moved it. It looks like it is in position. There are no gaps behind the top of the tank and the wall. It is almost empty, so it is easy to slide around, but I have pushed and tapped with a rubber mallet and it will not go back far enough to re-mount the metal brackets that were holding it in place. I need about 1/4" to put them back on with the existing holes. Is there a trick to this or should I just drill out new holes?

If I drill new holes, is there an easy way to seal them?

Thanks for any help.