full-width table of content for tufte-book

Question

Using the tufte-book layout, I wish to use the full width of the pages where the table of content is listed. There are a number of similar questions on SO (for example from which I used some of his example code, or here where Ulrike Fischer suggested part of a solution.

I found somewhere a suggestion that tcolorbox could be used and have found that it works, even in cases where the table of content is longer than a page.

I have a MWE which works nearly; can it be made to work correctly?

It does either

• insert multiple empty pages before the TOC starts (when using \tableofcontent), or
• starts without header (when using \csname @starttoc\endcsname{toc}) (if I add a \clearpage then I get multiple empty pages)

In either case, the text for the even pages is completely outside of the box.

\documentclass[nobib,twoside,symmetric,showframe] 
         {tufte-book}  
\usepackage{printlen} % to print geometry
\usepackage{calc}
\setcounter{tocdepth}{4}

\usepackage[]{mdframed}
\title{TITEL book level 1 BookTitle}
\author{Author of Settings}
\usepackage[breakable,most]{tcolorbox}
\usepackage{calc}
\begin{document} 
\frontmatter
    \vspace{1.5cm}
    {\huge\bfseries{TITEL book level 1 BookTitle} \par}     
    {\large \today\par}


%    \clearpage
    \tcbset{breakable,%
%           title=Content title,%
            width=\textwidth,%
            grow to right by=\marginparsep+\marginparwidth}
    \begin{tcolorbox}[toggle enlargement=evenpage]
%       \tableofcontents
%       \clearpage
         \csname @starttoc\endcsname{toc}
    \end{tcolorbox}
\mainmatter
\section{book title - one hash: vorwort buch v12345}
vorwort some text
\chapter{Questions of Design}
\section{(title section 1)}
\subsection{(title sub-section 1)}
\subsection{(title sub-section 2)}
\section{(title section 2)}
\subsection{(title sub-section 1)}
\subsection{(title sub-section 2)}
\chapter{Questions of Drawing}
\section{(title section 1)}
\subsection{(title sub-section 1)}
\subsection{(title sub-section 2)}
\section{(title section 2)}
\subsection{(title sub-section 1)}
\subsection{(title sub-section 2)}
\chapter{Questions of Technique}
\section{(title section 1)}
\subsection{(title sub-section 1)}
\subsection{(title sub-section 2)}
\section{(title section 2)}
\subsection{(title sub-section 1)}
\subsection{(title sub-section 2)}
\chapter{Questions of Design}
\section{(title section 1)}
\subsection{(title sub-section 1)}
\subsection{(title sub-section 2)}
\section{(title section 2)}
\subsection{(title sub-section 1)}
\subsection{(title sub-section 2)}
\end{document}