Yes, I had considered that, but in either case, I find it hard to make a precision adjustment anyway. Even on a 12.9″ iPad Pro, the box is quite small, and the movements required on the graph are also small and tricky, even using a Pencil 2.
I appreciate this is all limited by the size of the screen, and some compromise between the size of the image and the size of the sidebar needing to fit into the space.
Cheers