Vertically align characters raised with \stackrel

Question

I learned from Stefan's reply to Putting a character above another character to use \stackrel in math mode to do just that. I'm using that right now to mark segments of a word as having a high (H) or low (L) tone. In some words, however, the characters that I put H or L above are of different heights. How can I align the raised characters H and L vertically?

\documentclass{article}
\usepackage{amsmath}
\begin{document}
h$\stackrel{\text{L}}{\text{a}}$nd$\stackrel{\text{H}}{\text{l}}$
\end{document}

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EDIT: The accepted answer to Adjusting vertical and horizonal spacing in \stackrel suggests (like Barbara below) to use \strut for each element. When using double spacing, however, this raises the characters way too high.

\documentclass{article}
\usepackage{amsmath,setspace}
\doublespacing
\begin{document}
h$\stackrel{\text{L}}{\strut{\text{a}}}$nd$\stackrel{\text{H}}{\strut{\text{l}}}$
\end{document}

Answer 1

You can add a \strut to make them vertically aligned. Or add a \vphantom only when necessary.

This is a relatively low-level implementation:

\documentclass{article}

% cf. \oalign and \mathstrut in LaTeX kernel
\newcommand\textoverset[3][(]{%
  \leavevmode\vbox{%
    \baselineskip0pt \lineskip.25ex
    \ialign{\hfil##\hfil\crcr
      \scriptsize#2\cr
      \vphantom{#1}#3\crcr}}}

\linespread{3}

\begin{document}

h\textoverset{L}{a}nd\textoverset{H}{l}

h\textoverset[l]{L}{a}nd\textoverset[]{H}{l}% add a template manually

\end{document}