Thanks for the feedback!
#17 replaces the dot of the I with green dot (I'm liking this concept because if you ever need to drop the graphic element and just use the text for some particular situation, the green dotted I will still reinforce the brand).
For #18 I used a lighter font for 'recruiting services'.
And for #19 I tried out the idea of sepia tones. As for my opinion on sepia vs. green, I think that's dependent on the feeling you want to promote. The green is more modern, hip and suggests money. The sepia is warm, promoting trust and creativity. I like them both!
I did try to bring down the boldness of "Centrifuge" but it ended up looking weak against the logo elements. If you would like to see for yourself, please let me know or if you would like to try some similar but different fonts, I would be happy to upload a some new ideas.
Jason