You might use the "Alternate" chord area for any extra notations, but the app will only recognize and play the "Regular" chords. You can also use a longer measure to imply 8th-notes, but then of course you would only have 2 measures per line, and you can still only play 4 Regular chords. (By the way, you only need to insert the "S" command once - the chord width will remain condensed until you enter the "N" command.)

Cidrack Song - Unknown Composer