Why do you keep taking the server down and putting it back up again?
I try to keep the server popular. If it was up 24/7 people wouldn't feel like it's a "party" or something neat you have to attend at that moment.
It would probably keep 3-5 people on at all times but nothing like what we usually have.
It's the same reason I always keep the max playerlimit at 20-25, when the server is full people are constantly trying to join and the playercount doesn't drop. People also consider their position on a full server to be more valuable and are less likely to leave during the loading screen or upon spawning.
If you set it higher it will raise to 30 or so but then slowly lower to 0.