Indenting two-column footnotes in Memoir

Question

Using the Memoir document class, I would like to indent the text of all footnotes to the right of the footnote number. In this MWE, the footmark settings accomplish that for single-column footnotes. But when one uses the \twocolumnfootnotes command (uncommenting the command on the 7th line), none of the footnote text is indented after the first line of the footnote. So, I'm looking for the settings that would indent the two-column version in the same way that the one-column is indented. Thanks.

\documentclass[14pt,letterpaper]{memoir}
\setlength{\footmarkwidth}{1.8em}
\setlength{\footmarksep}{0em}
\footmarkstyle{{#1}.\hspace{1mm}} 
\begin{document}
\pagestyle{empty}
%\twocolumnfootnotes
Some sentence.%
    \footnote{A short footnote.}
Second sentence.%
    \footnote{Another short footnote.}
Another sentence.%
    \footnote{A long footnote. Using the \emph{plainfootnotes} standard in the Memoir class, the entire text of this footnote will be indented on the left. However, if \emph{twocolumnfootnotes} macro is used, only the first line is indented.}
A final sentence.%
    \footnote{So, how does one indent the entirety of a long footnote using the \emph{twocolumnfootnotes} macro?}
\end{document}

Answer 1

UPDATED after follow-up question.

Try this code.

\documentclass[14pt,letterpaper]{memoir}

\usepackage{showframe} % only to show the margins

\setlength{\footmarkwidth}{1.8em}
\setlength{\footmarksep}{0em}       
\footmarkstyle{{#1}.\hspace{1mm}} 

\makeatletter
\renewcommand{\@twocolfootfmt}[1]{% added <<<<<<<<<<
    \@preamtwofmt%
    \parindent\footparindent\noindent%
    \leftskip\footmarksep\relax
    \advance\leftskip \footmarkwidth \null\nobreak\hskip -\leftskip\relax
    {\footfootmark\strut {\foottextfont #1}\strut\par}\allowbreak}
\makeatother

\begin{document}
    \pagestyle{empty}   
    \twocolumnfootnotes
        
    Some sentence.%
    \footnote{A short footnote.}
    Second sentence.%
    \footnote{Another short footnote.}
    Another sentence.%
    \footnote{A long footnote. Using the \emph{plainfootnotes} standard in the Memoir class, the entire text of this footnote will be indented on the left. However, if \emph{twocolumnfootnotes} macro is used, only the first line is indented.}
    A final sentence.%
    \footnote{A long footnote. Using the \emph{plainfootnotes} standard in the Memoir class, the entire text of this footnote will be indented on the left. }
    A final sentence.%
\end{document