As far as i am aware you can't wire two Zv5 D1 down to .5 ohms.
You need the D2 but why do you want to wire down to .5?
Here is the wiring diagram for both
D1 - http://www.the12volt.com/caraudio/woofer_configurations.asp?Q=2&I=12#results
D2 - http://www.the12volt.com/caraudio/woofer_configurations.asp?Q=2&I=22#results