Estes Super Mars Snooper #7309, Build Part 5, Rounding The Upper Fins

Here's how the upper fins glued up - 

You can see the upper fairing was rounded and the larger lower fin still has squared edge.

On the right, I'm rounding the leading edge, feathering in the corner joint.

Here's two examples of the rounded inside leading edge joint.

The curved sides and back edges are easier to round with  

400 grit held by my fingers.

CWF was applied.

After sanding, that joint seam should end up smooth.