If you're going with the Z3 4-12x50 BT you might want to consider the 4W reticle which is available in that model.
Printable View
I have the 4W on my Z5... I'm not convinced and would prefer the 4A instead. Maybe I just need to use it more?
Got the 4-12, was meant to replace the Kahles on the 2506 but ended up on my 7mm mag.
Very happy with it.