How to get the devanagari sign candrabindu with velthuis mapping?

Question

I am typesetting the following document and, to my dismay, I hit this issue in its title!

1. See the example doc below. For now, I must use Velthuis mapping for typesetting in devanaagarii (as dictated by my current workflow which I am trying to improve, but that's for later).
2. I need the title of the doc below to be गॅलरी. I do not know how to map in Velthuis the devanaagarii sign candrabindu (unicode code-point 0901 hex (e.g. as in गॅ)). According to the Velthuis encoding scheme (as documented in Devanaagarii for TEX package Version 2.17), the encoding for candrabindu is ~a. But this does not work as ~ is rendered verbatim in the PDF (via xelatex).
3. I tried the workaround suggested in a similar question, but that does not seem to work. The title is rendered as .

I need it to render as

Can you suggest any workaround?

Minimum Example Source File

\documentclass[a4paper]{article}
\usepackage{polyglossia}
\usepackage[margin=10mm]{geometry}
\setdefaultlanguage{marathi}
\setotherlanguages{english}
\setmainfont[Mapping=velthuis-sanskrit,Script=Devanagari,Language=Sanskrit]{Shobhika}
\newfontfamily\englishfont{Lato}
% make sure ~ as non-breaking space doesn't interfere with velthuis-sanskrit mapping
\edef~{\string~}
\pagenumbering{gobble}
\begin{document}
\title{g~alarii}
\maketitle
\end{document}

Answer 1

\documentclass{article}
\usepackage{fontspec}
\setmainfont[Script=Devanagari]{Siddhanta}  %% use any other font in your OS.
\begin{document}
गॅलरी
\end{document}

You may use this helpful online editor to key in गॅ.

This file processes coprrectly using XeLaTeX.