You should use a glue that fills up the gap. Super glue needs a tight fit, so I wouldn't go there...
I don't know Gorilla glue, but I guess any epoxy type of glue wood fill the gap as if it has a plastic insert and would hold your frets pretty sturdy. But don't ever think about a re-fretting job.
Im not a fan of that stuff...
For wood repairs its great (not instrument). Otherwise i stay away from it
