Did a bit of modification to the script last December.
This is an unofficial script, of the parametric kind, which is useable in MoI, by shortcut key.

a_Scale changes the Scale of the Spiral.

The d_Factor is for daughter curves, and is not independent of a_Scale and t_Length. Different combinations can create the same curve.
Perhaps not so useful, but it can have a negative value.

For a 2D curve, set the z_Factor to 0.
For a 3D curve, set the z_Factor to a nonzero value, which can also be negative.
A z_Factor of 1 causes the curve to rise in the vertical z direction by 1 unit per 90 degrees, (I think).

Negating a_Factor, d_Factor, and/or x_Factor, flips or mirrors the curve.

Disabled the slider Accel.C, acceleration of curvature. It did not seem to be of much benefit...
For an Euler spiral, the value is 2.0.

Checked that the script does work in MoI2.

Length adjusts the arc length, in 2D. In 3D I think the arc length is longer, but the projection is the same length.

Made a quick scroll, with Blend for the ends. Blend seems to be a very powerful tool.