Your first test was not a valid test of the dial-peer redundancy. dial-peer redundancy kicks in when an H.323 gateway can't connect to the CallManager. However, in this case if you configured a route pattern in CallManager to block this call, then CallManager should send back the appropriate signal (ie unassigned number) and reorder tone will be played.
Instead of configuring a pattern in CCM to block the call, just unplug the primary CallManager from the network or stop the CallManager service. Note: this should only be done during non-business hours or in a lab environment.
I'm not sure why your 2nd test wasn't successful. Did you configure the following as mentioned in the techtip?
voice class h323 1
h225 timeout tcp establish 3
dial-peer voice 100 voip
preference 1
voice-class h323 1