A colleague of mine alerted me of your question, and I've updated the widget to support custom options. You can now append your own values to the options object that will be passed onto the Google Chart, as explained here: https://developers.google.com/chart/interactive/docs/customizing_charts.
As an example:
In this example a few items are added to the options, and the "showRowLabels" that was already provided as an option is actually overwritten.
I hope this helps!
Sounds like it would be a relatively easy modification to the widget. You could take a crack at it yourself, or make the request to Bizzomate on the Github page for that widget.
Hi guys! how do i place a vertical reference current timeline in google chart timeline?