Value of backlinks from same article directory?

What is your view on having multiple articles targeting the same keyword(s) from the same article source? I.E ezine


-Background - Ecommerce site targeting min ~300 words, ~1300 pages indexed by google, site is ~7 Months old. AVG 100 visits per day.
-I have tons of keywords at 11-13 position that need to be pushed over the edge to the first page to gain momentum.

When the account becomes bigger/contains more content the backlinks will become better. For example hubpages needs a score of 75 point to make a link become ********. if it does it's a hq backlink

so how many articles need to get 75 points?