I'm using booktabs and colortbl. I'm get a very annoying problem of the color table overlapping a horizontal rule. Maybe pixel snapping problem or something, but I can't make it go away. And I appreciate that rules and color in the same table are typographically suspect, but let's please pretend otherwise for a moment.
Here's my MWE:
\documentclass{article}
\usepackage[table]{xcolor}
\usepackage{tabulary}
\usepackage{booktabs}
\begin{document}
\begin{center}
\newcolumntype{G}{>{\columncolor{gray!15}[0.9\tabcolsep]}C}
\newcommand{\mythickrule}{\specialrule{1em}{0em}{0em}}
\newcommand{\whiterow}{\rowcolor{white}[0.9\tabcolsep]}
\begin{table}
\begin{tabulary}{\linewidth}{LG} \mythickrule
\whiterow foo & stuff \\ \mythickrule
bar & stuff \\ \mythickrule
\end{tabulary}
\end{table}
\end{center}
\end{document}
Here's out it looks for me. Notice the little nubs and cutouts. How do I clean this up so colors and rules are flush?

I found a related link, but this didn't lead to an answer for me:
