For those who want a "next testimonial" link, to skip to the next testimonial in the rotation, this is what I did.
Add this to your header or footer:
The function name "nextTestimonial100000()" will change based on the instance of the widget you want to target.
Now where ever you want the next button be (for me, below the testimonials) you will need to add an HTML element with the class "next-testimonial"
Also this doesn't turn off the rotation only initiates it early, so if you want to disable the auto-rotate, I suggest setting the interval to a high number (e.g. refresh_interval=99999999)
I added a next link because by testimonials are longer and various lengths, so the timing is tricky. Also I wanted an indicator that there are more testimonials.