^ Let me explain why hiring a signature campaign manager is better than they are managing itself, first because a professional campaign manager knows the participants if they are good posters or not, the campaign managers know which is spamming or not and they have their own rules that participants should be followed. On the other hand, don't expect if you are running signature that there is an effect after a week because most likely you will see an effect after months or onward. The longer you running a campaign much better.
True, that's why I agree with Fatfork that hiring a professional campaign manager is the most recommended between running the campaign themselves or hiring a pro campaign manager. I have seen a project where they did manage the campaign themselves but the results is different from hiring a professional. Since you pointed it out why hiring professionals is much better than managing the campaign themselves then my guess is they will hire professionals to manage the campaign.
Hiring a professional campaign manager would be a big help for they will be able to handle the project appropriately and the managers could closely monitor their participants' performance tasks each week. The campaign manager could polish the whole campaign better than doing it themselves wherein they have a lot to focus on. A professional campaign manager has a huge role in the good run of a certain project.