Perhaps just combine them all once to get a total area to use for your calculations.
Then you would need to have a field in each layer for the percentage.
Run the calculation.
Create a classification for one layer with the min max, and define specific breaks.
Maybe 5 classes.
Create an lyr (layer) file for the first one and apply it to each subsequently.
This would depend on you using the same field name for calculating the percentage in each layer.
I may be wrong but it seems that you might want to sum all the areas of one layer and show that percentage as a class.