How many posts do you make approximately in a month? And where do you post more often? In which section? And do you want upfront payment?
I usually make 50+ posts per month as I am currently very active & the majority of them aren't useless posts, I usually post in the Alternate cryptocurrencies & also the Announcements (Altcoins) Threads
After reading a heap of Signature services I doubt anyone will pay upfront as most have the conditions of a required number of substantial posts plus Weekly/Monthly payments thereafter.
I'd be happy to "Reserve" my spot in an upcoming campaign !