Hi
depending on what keyboard you own, ever thought about having the chord progression in a variation itself, ( to free up your hands for harmonic) ie settings like the intro's.
Would probably make it song specific, but so what.
Tried it a few years back on my pa800 with a midifile. Cut it into verses and chorus etc
Vari 1 verse, vari 2 chorus . No chord changes. I put just about the whole song into this style.
But don't see why one of the variations couldn't be recorded with chord changes and put into the style, rest of style left as per normal.

Naturally a chord sequencer would be easier, but.