in line with the message of Dimitry, I would
guess pseudosections are the most suitable
approach for these high variance assemblages.
As an inspiration you may have a look on our work
on granulites from western Africa, using a
combination of avPT and pseudosections. Although
the dominant assmeblage is a HP granulite one,
the LP granulite overprint is dealt with as well:
Pitra, P., Kouamelan, A. N., Ballèvre, M. &
Peucat, J.-J., 2010. Palaeoproterozoic
high-pressure granulite overprint of the Archean
continental crust: evidence for homogeneous
crustal thickening (Man Rise, Ivory Coast).
Journal of Metamorphic Geology, 28, 41-58.