sidesubfloat: how to change the space between the label and float?

Question

In the example below, how can I change (say, increase) the spacing between the labels and the floats? I tried tweaking the capbesidesep parameter, but it seems to have no effect. Thanks and regards, Jorge.

Example:

\documentclass{article}
\usepackage{floatrow}

\newlength\mysep \setlength\mysep{1cm}
\DeclareFloatSeparators{mysep}{\hskip\mysep}
\floatsetup[figure]{style=plain,subcapbesideposition=top,capbesidesep=mysep}


\usepackage{subfig}
\usepackage{graphicx}
\begin{document}
\begin{figure}
\centering
\sidesubfloat[]{\includegraphics[scale=0.25]{example-image-a}}
\\
\vspace{1cm}
\sidesubfloat[]{\includegraphics[scale=0.25]{example-image-b}}
\end{figure}
\end{document}

Output:

Answer 1

You could modify \labelsep to change the space between the label and the image:

\documentclass{article}
\usepackage{floatrow}

\floatsetup[figure]{style=plain,subcapbesideposition=top}
\setlength{\labelsep}{3cm}


\usepackage{subfig}
\usepackage{graphicx}
\begin{document}
\begin{figure}
\centering
\sidesubfloat[]{\includegraphics[scale=0.25]{example-image-a}}
\\
\vspace{1cm}
\sidesubfloat[]{\includegraphics[scale=0.25]{example-image-b}}
\end{figure}
\end{document}

Answer 2

I have put into \sidesubfloat[] an horizontal space of 1 cm \hspace{1cm}. Could it be a convenient solution for you? I hope I have answered your question.

\documentclass{article}
\usepackage{floatrow}

\newlength\mysep \setlength\mysep{1cm}
\DeclareFloatSeparators{mysep}{\hskip\mysep}
\floatsetup[figure]{style=plain,subcapbesideposition=top,capbesidesep=mysep}


\usepackage{subfig}
\usepackage{graphicx}
\begin{document}
\begin{figure}
\centering
\sidesubfloat[]{\hspace{1cm}\includegraphics[scale=0.25]{example-image-a}}
\\
\vspace{1cm}
\sidesubfloat[]{\includegraphics[scale=0.25]{example-image-b}}
\end{figure}
\end{document}