Rear valance joints?

[lexxman]

I'm installing new rear valance and corners.There is a gap of about 1/4 " between the corner and the valance.And the joints between the corner and the 1/4 panels are good.What do you do with the gaps?Do you use sealer or body filler?
Some people say to filler them and then re-cut them after.
Thoughts?

[Patronus]

We've just isolated our gaps to behind the bumper ...so yeah, seam sealer I reckon. Our valence doesn't have quite the 90 bend as the corner does. (all AMD)