Clearing point column in exam document class

Question

Question: Is there a way to "clear" the contents of the points column using the gradetable for the exam document class?

Edit (2): I was able to use some code from exam.cls to print a table that uses a given number (9 in this case), but I'd like to not default to 0 if no point value is given for a question but just an empty space. If I try that instead of the 9, then I get ! Missing number, treated as zero error. I feel like I am close to a solution to my problem, but I am having a hard time working it out. (See end of this question for new code and output.)

---

Using the code

\documentclass[addpoints]{exam}

\begin{document}
\gradetable[v]
\begin{questions}
\question[10] Question 1
\question[20] Question 2
\end{questions}
\end{document}

produces

Though it may sound odd, I'd like to be able to clear out the contents of the points column (so I only have empty boxes or spaces). I tinkered with a number of things including \pointformat and looked at a few questions on TeX.SE about how to "hide" the point totals in the document body itself (i.e., not printing the points in the margin), but I cannot come up with any fix to have each point value printed in the table as {} or something similar.

Is there a way to do this using \renewcommand or something of that nature? [I don't have the know-how to fully understand the package code itself to know what command to "renew" that ends up printing the point values in the table.] (I'm ultimately trying to take advantage of the exam gradetable structure, but I cannot figure out a way to alter the table as communicated.)

---

Edit (2):

The above is produced by the following:

\documentclass[addpoints]{exam}

\makeatletter
\renewcommand*\set@hlfcntr[2]{%
  \begingroup
    \global\csname #1@halffalse\endcsname
    % If there as a `\half' present, it will be executed
    % right after the assignment of the digit part of #2
    % to the counter #1.
    \def\half{%
      \global\csname #1@halftrue\endcsname
    }%
    % We insert a `0' in case there are no digits present:
    % We avoid using \setcounter, because calc.sty redefines
    % \setcounter in a way that conflicts with the \half trick
    % we're using:
    %    \setcounter{#1}{0#2}\relax
    %%%\global\csname c@#1\endcsname 0#2\relax%%% <== ORIGINAL CODE
    \global\csname c@#1\endcsname 9\relax
  \endgroup
}% set@hlfcntr
\makeatother

\begin{document}
\gradetable[v]
\begin{questions}
\question Question 1
\question Question 2
\end{questions}
\end{document}

Answer 1

Updated to also cover partial tables. Note that the order of the arguments for \emptypartialgradetable and \emptypartialbonusgradetable differs from the corresponding macros in the class - here, the optional arguments come first, before the range. That is because I used \newcommandtwoopt to define them.

\documentclass[addpoints]{exam}
\usepackage{twoopt}

\makeatletter

\newcommandtwoopt{\emptygradetable}[2][v][questions]{{%
  \renewcommand{\pointsofquestion}[1]{}
  \renewcommand{\prt@tablepoints}{}
  \@scorestrue
  \@bonusfalse
  \@partialfalse
  \@combinedfalse
  \ii@gtable{#1}[#2]%
}}

\newcommandtwoopt{\emptybonusgradetable}[2][v][questions]{{%
  \renewcommand{\bonuspointsofquestion}[1]{}
  \renewcommand{\prt@tablebonuspoints}{}
  \@scorestrue
  \@bonustrue
  \@partialfalse
  \@combinedfalse
  \ii@gtable{#1}[#2]%
}}

\newcommandtwoopt{\emptypartialgradetable}[3][v][questions]{{%
  \renewcommand{\pointsofquestion}[1]{}
  \renewcommand{\prt@tablepoints}{}
  \@scorestrue
  \@bonusfalse
  \@partialtrue
  \@combinedfalse
  \def\tbl@range{#3}%
  \ii@gtable{#1}[#2]%
}}%

\newcommandtwoopt{\emptypartialbonusgradetable}[3][v][questions]{{%
  \renewcommand{\bonuspointsofquestion}[1]{}
  \renewcommand{\prt@tablebonuspoints}{}
  \@scorestrue
  \@bonustrue      
  \@partialtrue
  \@combinedfalse
  \def\tbl@range{#3}%
  \ii@gtable{#1}[#2]%
}}%

\makeatother

\begin{document}
\emptygradetable[h]

\bigskip

\emptybonusgradetable[v]

\bigskip

\emptypartialgradetable[h][questions]{myrange}

\bigskip

\emptypartialbonusgradetable[v][questions]{myrange}   

\bigskip

\begin{questions}
\question[10] Question 1
\question[20] Question 2

\begingradingrange{myrange}
\bonusquestion[15] Question 3
\question[10] Question 4
\question[15] Question 5
\endgradingrange{myrange}
\end{questions}

\end{document}