Making more hairstyles is really simple! You just need to:

1) make them with higher numbers than the styles provided by this mod

2)patch the species file to allow for the higher numbers of hair options

3)congradulate yourself on a job well done!

It should even be independent from this mod at this point; which means: even people using vanilla races will be able to enjoy your great work!

The mod authors will likely admire your initiative and congradulate you as well, smiling inwardly that their mod inspired creativity in you!