Never pay anyone a flat fee weekly or a per word price. Neither will get you what you want.
Instead, set out how many posts you need done along with the style and general length. Set a deadline, agree on a price for the project and get it done. That way you have cost certainty, you know exactly what will be written and when it will be completed. The text will be better and the parameters to grade it are simple. If the writer performs well... rehire them, if not... don't
If you want to discuss your specific project... contact me at
www.EngineFood.com
You'll see 12 pages of testimonials and GFY threads like this one
https://gfy.com/showthread.php?t=1098107 all about the quality service Engine Food provides for our clients.