Not a lot of H here, but I think page 7 means it shouldn't go to non-h.
I have no idea about the circle/author who created it.
I copied the ○ that's used in http://www.suruga-ya.jp/product/detail/ZHORE20316, but I don't know it's a circle's name or it means they don't have the information.

Someone tagged kurokawa mio as the artist, but did not bother to comment.
http://www.doujinshi.org/browse/author/998/Kurokawa-Mio/

The dojin itself is not in mugi

Base +50

Well regarding pgs 5-7, that could have been an interesting direction for the series to go in ;)

Base +5, HXW +7

Circle is literally ○ (maru). The doujin was released at Comiket 48.
Credited artist is 黒雅 (kokuga or kuroga???), but the Kurokawa Mio name is also appearing in the credits page, with no role mentioned.

The oldest Kurokawa Mio doujin we have is from C57, that's much later, no connection can be made.

Base +34, TheGreyPanther +61