The duration of the campaign is one month only, and the amounts to be paid have not been determined yet, but the minimum payment is $ 25 per week for a member and the number of posts is only 30
30 posts per week, I guess that's too high for a payment of $ 25, I suggest you decrease the post requirement and hire more posters, that way it could minimize the spam it could possibly make. I'm just saying based on my observation in the past, most signature campaigns now have only 25 post maximum per week, some even have pay per post and a minimum of 10 post while 25 is the maximum to get paid.
You don't need a lot of post really, what you need is quality posters that could add quality on the project you are advertising.
My 2 cents.