How to make this shape without seams?

[gsingh2011]

I'm trying to loft between two of the profiles in the image below, with the third arc being the rail.

The result looks like this

I mirrored this to get this result

How can I get rid of the edge/seam in the center, so that it's a smooth transition between the mirrored halves?

I also tried to use sweep/split body instead of loft. I get this shape with no seams

But you can see here the shape isn't exactly right

I've attached both files.

[jhackney1972]

See if this model suits your needs.  Model attached.

[TrippyLighting]

Mirroring fit point splines is a bad idea!

After editing one side, often the symmetry is lost.