Parking brake adjustment

I have 96 Chevy Silverado 1/2 ton 2wd w/164k miles and 5.7l engine. I recently put new drums and shoes on it and now my parking brake pedal goes all the way to the floor. I was told it is self adjusting and would adjust after braking in reverse for a couple of days. It's been a week and still the pedal hits the floor. I don't believe I made a mistake reassembling anything. I did have to adjust the "star nut" almost all the way in to get the drum on. Do I need to be more patient? Is there a certain speed that has to be met for the adjustment braking in reverse? Are there other adjustments?