Titlesec - vertical align \chapter and \section

Question

I've found a nice \titlesec style for my chapter that I want to use for my thesis. Unfortunately the \chapter text doesn't align vertical with the \section text:

(I've added the red line in paint to demonstrate the problem).

I know that it's very close and I could fiddle with the \hspace of the \chapter from the line \newcommand{\hsp}{\hspace{9pt} but i feel that it would never be 100% perfectly aligned. What would be an elegant way of doing it?

MWE look like this:

\documentclass[12pt,a4paper,twoside]{report}
\usepackage[utf8]{inputenc}
\usepackage[german]{babel}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage[left=4cm,right=2.5cm,top=2cm,bottom=2cm,bindingoffset=6mm]{geometry}


% Style for Chapterheadings
\usepackage{titlesec, blindtext, color}
\definecolor{gray75}{gray}{0.75}
\newcommand{\hsp}{\hspace{9pt}}
\titleformat{\chapter}[hang]{\Huge\bfseries}{\thechapter\hsp\textcolor{gray75}{|}\hsp}{0pt}{\Huge\bfseries}
%%%


\begin{document}

\chapter{Beschreibung des Geschäftsprozesses}
\section{Übersicht über das Arbeitsumfeld des Geschäftsprozesses}

\end{document}

Answer 1

You can box the numbers to a certain width.

\documentclass[12pt,a4paper,twoside]{report}
\usepackage[utf8]{inputenc}
\usepackage[german]{babel}
\usepackage[T1]{fontenc}
\usepackage{amsmath}
\usepackage{amsfonts}
\usepackage{amssymb}
\usepackage[left=4cm,right=2.5cm,top=2cm,bottom=2cm,bindingoffset=6mm]{geometry}


% Style for Chapterheadings
\usepackage{titlesec, blindtext, color}

\definecolor{gray75}{gray}{0.75}

\titleformat{\chapter}[hang]
  {\Huge\bfseries\filright}
  {\makebox[40pt][s]{\thechapter\hfill\textcolor{gray75}{|}\hspace{9pt}}}
  {0pt}
  {\Huge\bfseries}
\titleformat{\section}[hang]
  {\Large\bfseries\filright}
  {\makebox[40pt][l]{\thesection}}
  {0pt}
  {\Large\bfseries}
%%%


\begin{document}

\chapter{Beschreibung des Geschäftsprozesses}
\section{Übersicht über das Arbeitsumfeld des Geschäftsprozesses}

\end{document}

I added \filright to avoid hyphenation in titles.