I'll try another way and hope it doesn't get too far afield.
In the gas turbines that use giant fan blades (ala propellors with many blades) they are both highly cambered and highly twisted to accomodate the significant variations in surface speed beween their root or hub mounting location and their tip or duct case location.
Where the blade surface speed operates near supersonic at the tip the blade is mostly flat faced on either side. If you look real close you can make out an airfoil like surface, however it's thicker toward the trailing edge than at the leading edge.
When you get to the inner hub or attachment location, the blade has a high degree of camber (curvature) and its cross section is thicker towards the leading edge vs the trailing edge.
The camber or curvature has a convex (outer side) towards the low pressure or entrance air and a concave or inner side towards the high pressure or thrust side..
With propellors that reverse by changing the twist angle, I would suspect that you would want less camber to effectively work in either drection.
Anybody else feel free to jump in.