Sankey Diagram Help

I was hoping that someone could point me in the right direction for how to achieve the following with a Sankey diagram.

I have a working diagram but it needs modifying in several aspects:

  1. I can position the nodes using the X and Y values but this positions the node centre. Is there any way to specify the position of the top of the node? I’d like to have everything nicely aligned and am struggling with this at the minute.

  2. My data have values of 1000s but then a few nodes have very small numbers. Is there any way to have the diagram NOT scale the node height by it’s value but instead by some arbitrary height?

  3. I’m creating this in python and saving to PNG. This obviously loses the hover capabilities. Is there any way to output as text next to the node the values that would have been on the hover?