How to manage the labels of stacked graphs?

I have multiple stacked graphs for which I would like to display the labels of each part of the graph,

Here it works:

But here as you can see the two stacked graphs values are entering into conflict:

How could I do to display both values, the one from the red graph and the other one from the blue, without them conflicting with each other ? Thank you.

A side question : how can I force the numeric value to be displayed on top of the graph ?