I hope this is not all redundant information, but I haven’t seen it in the forum yet (I’m pretty new). Strum Machine is quite popular with the Old Time fiddle tune crowd. At it’s heart, that’s dance music, oriented toward dances that come in two forms. On one hand, contradances have specific structure and accompaniment for them must respect and support that - the tunes cue the dancers and are in four with eight (sometimes sixteen) bar sections. Strum Machine is perfect for this. On the other hand, square dances depend on callers for the cues, and do not require strict metric structures - mostly just a steady beat. As a result, there are many many “crooked” tunes, that is, tunes with odd length (3 beat, 5 beat, 6 beat) measures and perhaps irregular section lengths. This presents a challenge for transcribers, who must decide how best to allocate the beats among measures and sections to accurately represent the phrasing of the tune. In their massive (1,406 tunes) “Collection of American Fiddle Tunes” Clare Milliner and Walt Koken addressed this problem in a somewhat controversial but elegant and effective way: no bar lines at all. Just the underlying beat and the melody’s overlying rhythmic notation. Of course I don’t know your algorithm for placing chord changes, and it may be impractical. But if users could establish a number of beats for a section (such as seventeen, or twenty-nine) and place chord changes over beats of our choice I believe it would work well for the legions of Old Time fiddlers, banjo players, and guitarists who love Strum Machine almost as much as we love the old crooked tunes.
I think you know this, but for others reading this: Strum Machine handles crooked tunes just fine with the “half measure” function, accessible under the Chart menu in the editor or with the H key. There are plenty of examples in Strum Machine’s library; see Elk River Blues, Five Miles From Town, Jeff Sturgeon, and Sweet Marie, for example.
This approach does mean you have to make the decision of which beat is considered “extra” and outside the regular one-two pattern of downbeats. But Strum Machine needs to know that anyway in order to alternate bass notes and play automatic bass runs (if configured) properly. Even the most crooked tunes are not devoid of phrasing, which is what the one-two grouping communicates.
You could drag-select all the chords and use the Chart menu to make everything a half measure. That’d put bar lines between every chord, and also eliminate alternating bass notes and bass runs as a side effect. Not what I’d want, personally, but it’s an option.