Good question. The first thing is you need to define what it is you really need. The title is less important and not universal anyway. In general it may be a person with marketing and technical abilities. There is a big difference if they come from one or the other. Other people may just have an ability to create new models that get faster results. If your startup needs this "growth hacking" on the technical side make that clear to attract the right person. For most, I think the strategy and marketing side is more useful since people have been hugely successful with mediocre products if positioned right. Feel free to contact me to talk about your project.