I know one is closer then the other... but that just looks like an uneven pair to me

I would agree, actually. The foreshortening isn't consistent. It makes it look like a plastic surgeon gave her a mismatched pair of implants.

Not only is one closer than the other, she's holding the strap as well, while the farthest one is loose.

And besides, it's common knowledge that breasts tend to have one in the pair that's bigger than the other, and that artists screw up.

It seems that Yamasaki Masato is actually a writer. If you check out his homepage at http://www.yama3.sakura.ne.jp/ you'll see that he works with a lot of artists, writing the stories for their comics. Also he says as much in his profile.

The kanji '作画' means 'artist' and '原作' means 'writer'.
There's a circle named after Yamasaki Masato(山咲まさと), the 'dennou yamasaki gumi'(電脳山咲組, 'cyber yamasaki team'), seems to be a group of artist cooperating with yamasaki, including Mr. Izayoi.
So don't just tag 'Izayoi_Seishin(十六夜清心)' on every picture from the pixiv id '山咲まさと'.
Here the artist of this picture is Shinobu(詩乃譜). Below is the doujinshidb page for this artist.
http://doujinshi.mugimugi.org/browse/author/29088/