I switched over to using incoming calls with callcentric and outgoing currently as well callcentric.
I like that callcentric is 2 bucks for unlimited incoming calls and that works well and I'm on pay as you go outbound but I wanted to be able to dial a special number for using google voice when I don't want to chew up my callcentric minutes.
Here is my current outbound route
{911:sp2},{([1-9]x?*(Mpli)):pp},{**0:aa},{***:aa2},{(<**1:>(Msp1)):sp1},{(<**2:>(Msp2)):sp2},{(<**9:>(Mpp)):pp},{(Mpli):pli}
I originally had callcentric for 911 and never used it but callcentric is still on sp2 and I now want to have GV as my secondary option.
If you set PrimaryLine for the Phone port to SP2 Service, then outgoing calls will use Callcentric by default. Then, if you dial **1 before a number, that will go out on Google Voice.
You can also set a speed dial to e.g. sp1(12123456789) and that code will also use GV.