Instead of unlocking as needed, try a schedule. Maybe try for a week and see how the population fluctuates. I feel the more certainty there is the more likely the population would increase. Another suggestion would be to maybe lower the population to 100 or so. I dont know anything about the costs of servers, but thought it might help. Keeping s2 up is a good way to try and increase total pop. Lastly I would suggest to try and maybe say a estimate as to if the server may or may not shut down and when that might happen. I dont like to play s1 because i have no houses and some other people who play s2 may agree and maybe if the server has more certainty more people would play it and invest into it. I didn't revise this so if it redundant or anything idc.