I would recommend to hire experienced bounty manager
Hiring a manager seems like an awesome idea but what bothers me is that this way you, probably, won't learn how to do things yourself. I'm also curious about the issue OP mentioned and it would be really helpful if someone could explain a bit more, what are the functions of bounty manager? Basically, he's gonna control the whole thing in all the social media and all the participants? That seems like a lot of work for just one person..
Good point. But if we talk about OP case - he aren't planning to become bounty manager, they only planning to launch bounty to promote their own ICO. So, they wont need this knowledge how to run bounty in future.
I'm not sure how to become bounty manager, but well, everyone started from zero. It's not easy job. I heard that some managers have written bots to manage social media campaigns. But still, signature campaigns, translations and content campaigns requires to make manual reviews and check everything. As I know, some managers have assistant to make their job easier.