I need meaningful Comments posted on Blog Posts to generate website leads

Num. of words: 80-100 words per post
Topic: Charitable Causes and People in Need
Tone: Sincere
Outline & Structure: The website URL is http://www.giftandbefriend.com/

We are looking for generalist writers to post comments for us on the Blog Posts of a wide variety of Blogs that others write, for the purposes of generating new traffic for our website. Ideally, we would like these posts to be written on Blogs that in the Charity/Giving niche, but the broad-based appeal of our website means we are interested in generating exposure on any blog that may stimulate interest in our site. You would identify these Blogs yourself, but we can recommend ways in which you can identify thousands of Blogs on a wide variety of topics, if you wish.

We are not looking for you to posts 'salesy' Comments on these Blogs, but instead post meaningful Comments which add to the discussion about the Blog post topic. The URL link you would post with the Comment would link back to our site.

It would be helpful if you could state in your proposal roughly how many Comments you believe you could post per hour.

Regards,

Brad.
Extensive research needed: no
Extra notes: Native English Speakers only please. Experience at blogging would also be an advantage, so feel free to name any blogs you write for when responding. Longer term contracts are available for freelancers who perform well during this initial exercise.