So I'm fairly new to riding a sports bike, and wondering how bikers normally deal with the visibility in mirrors when ducking down and sitting in a more upright position?
Each model is different. You have to play around to find the sweet spot.
My first 3 bikes all had mirrors that were useless, only gave a view of my arms no matter how they were adjusted, the best I could do was to twist to one side then I could see past my body in the mirrors. My current bike (Ninja 400) is much better in that I can actually see whats happening behind me whether I'm tucked in or upright.
I know there are "extenders" that you can fit on your bike if you want to move the mirrors more outward for a better view, that may help you.
But right now I'm looking for tiny blind-spot mirrors. Just like the ones you get for cars, but smaller of course.