Ther are many factors.
1.What time of year and where are you located?
Here on Eastern Long Island it's getting light at 4:30 in late June,but by Labor Day sunrise isn't until 6:17.
We start play at 7 am on weekends(Fri-Sun) and 7:30 on weekdays in Peak Season (Memorial Day-Labor Day)
then go back to 7:30 and 8:00
In Augusta Ga, where I grew up, the sun doesn't rise until 6:54 tomorrow so it's difficult to see how they could handle a 7 am start regularly
2. How fast are first groups out and are they solid or will there be gaps?
we do two ball speed slots on weekends and we ask the first group to turn in exactly 1 hour and 30 minutes to prevent them running over the crew.Pretty much all our speed slots are at or near this pace so there really isn't a gap to work in once caught,
on a busy summer weekend there will be no first tee gaps until 11 or 12.
In late August, when we are very busy, the declining daylight/late sunrise makes it a challenge to stay ahead of early play.
3. How much work is going to be done/expected by membership?
4. Crew size