When is the earlist time normally people go in and put name down on a list on weekend mornings?

I was there 15 min after opening on Saturday

Depends on your group size and the day of the week. Groups of 2 move faster than larger groups sizes. Any time after opening would be around an hour wait on a weekend.

People start lining up 20-30min before opening on weekends. By the time the doors open, there can be up to 30 people in line. A weekday morning is always better. But despite the wait, it is good!