Hi Chris --
I watched the E383 Style video obsessively. Yamaha seem to use a modified Nashville-type numbering system. Here's some chord progressions that I spotted:
1645 C Am F G #1
1625 C Am Dm G
1564 C G Am F
1524 C G Dm F
1415 C F C G
1151 C C G C
1b741 C Bb F C #7
2615 Dm Am C G #8
2514 Dm G C F #9
4536 F G Em Am #11
4566 F G Am Am #12
16451 C Am F G C #23 "Fields of Gold"
1241 C Dm F C #24
4251 F Dm G C #25
1625 C Am Dm G #27
1524 C G Dm F #29
1415 C F C G #30
m1637 Am F C G #37
m1765 Am G F E
I hope I transcribed those correctly. Ujiie is well-known for fast-fingering buttons.
Auto-Chord Play has a parameter which specifies the number of beats to hold each chord: 2, 4, or 8 beats.
The E383 lets you set the key signature for the style to be played. Hopefully, Auto-Chord Play transposes according to the key signature (C/Am or whatever).
Amazing what can be done with 4 chords -- pj