Best Social Sharing Website

Hi guys

I am looking for the best social sharing exchange for twitter, fb and Google Plus. Linkedin is optional but I am basically just want to hear some recommendations on the best way to do this.

The plan is to pay for credits for the best services and only get a small amount of shares per url on my blog (about 15-40 per url). I have a few requirements:

1) I need it distributed over a long period. (2-3 weeks)
2) I need the shares to appear on semi decent social profiles. I understand that a large number will be bots but it would be great if I could set the minimum followers (easyretweet does this for twitter) to ensure its not a blank profile.
3) I need the shares to stick.

As i mentioned, I dont mind paying for this service. Whether it be credits or a service that somebody offers here, I dont really mind, as long as the above requirements can be met.

Any recommendations, suggestions or ideas are welcome.

Thanks!

P.S: The good news is that my posts are extremely high value. They are about 2200+ words, completely original, well laid out with multiple images and I even offer a 24 hour reply time on anyone that makes a comment (asking a question) on the article. Realistically, my posts usually get natural social media exposure (my latest one is sitting on 22 G+ shares for example) but I would like to beef a few of them up in the most natural way possible, while spending minimal time doing so as I like to rather spend my time writing and working on other business ventures.