Okay, after more thought, I'll use a tootsie roll analogy.
Place a helix around a short cylinder, with the desired number of turns, x.xxxx.

Place a line segment on each end, from the center axis outward.

Connect each helix end to one of these line segments, with another curve.
suggest MoI tapered helix command, or maybe variable pitch helix script, _VarPitchHelix.

- Brian

Or just use the tapered helix?