Here is an update to the MoI script version, PropDesignGeoOptionA.
It uses Option A, pre-calculated "tangent" points, which is probably better than trying
to find the points by arc, or circle interception, as there could be zero or two intersection points.

Most of the coding for the previous version was re-used, with slight change, except for the four arc intercept coding.

The mirrored tangent points were easy to get, just negate the y values. The arcs are on both sides, no need to mirror them.

I think it would be easy to script mirror the airfoil spline, with the mirror factory...

On a side note, still trying to figure out how to extract the x, y, and z values, from a given point.
Either vector math, or the "get" method in point?