I have the Rapid Z (also called the #20 in Zeiss literature) in my fixed power 4X32 Conquest, and I think it's one of the best plex style hunting reticle designs available for a second focal plane scope. To me, the thick posts are just the right thickness for good visibility in low light without being so thick that it obscures too much of the target. I like the spacing Zeiss chose for the thin crosshair section in the center. The thick posts don't go so far toward the center that they obscure a lot of small targets, yet they go close enough to the center so that when you begin to lose the thin crosshairs in low light, you can still center up the reticle on a game animal and make a shot. I like the fact that the thick posts have a nice taper toward the thin crosshairs, which are thin enough in the center for precision shooting.
Here is a visual of the Conquest reticles: