The ladder is more appropriate because traditional music doesn't modulate far, never goes round the circle, rarely uses the extreme keys and never presupposes equal temperament, which has to be assumed for the circle to close.

The ladder design is tailor-made for making slide rules. Something a bit like it is described in Athanasius Kircher's Musurgia Universalis of 1655 - a set of calculational "bones" designed for harmonizing tunes.