Love it! Just wondering how to change the min length when doing batch renders. I see the settings for this but can't seem to make a difference. Most songs end up as very short.
The length of the song is determined by the song structure and the different length and count parameters.
If you want to make the songs longer you can take a look at the song structure for the "Sentimental" song template, which uses some more parts (and also probabilities for them to exist at all within a song). Then you can also change the various "Length and Counts" to modify the number of possible phrases within each part and also the number of measures for those phrases.
I know that this is rather tedious, and I wish that there was a more intuitive option available for controlling the song length.