I think the Charleston sound come mainly from the melody.There always seems to be a rest on beat 2 which provides the syncopation.

I have a medley of Charleston, Black Bottom and Ballin' The jack, all 20's era songs with the typical Charleston sound. I played it with half a dozen 4/4 sw8 styles from jazz to country and rock, real and Midi They were all acceptable to some degree. Even without the melody they still feel OK.


BIAB for Windows Version 2019 (643)
Windows 10 (1909)