I need help determining the expected original gravity for a stout.

Hi,

I'm in the process of coming up with my own recipe for a stout, and the malt I want to use is Briess Traditional Dark LME. I also will want to steep C-40 and and Blackprinz. However, I cannot seem to find resources for their respective PPG's. How do I determine how much of each I should use if I want the original gravity to be in the 1.060 area?

EDIT: For the purpose of my logbook, I'd like to know the PPG's for each so I can do the calculations myself.

Thank you!