Wow, great news @pharesim. I have tried to register my wife through the regular Signup process, but it has been over a week now. Great that I can invite a friend easily now. I have a couple of other friends that would like to join.
One question though. If I delegate 14.5 SP, what happens if I undelegate it after inviting? Or is it not possible?
It will stay for 30 days minimum, even if you undelegate immediately.