indenting verbatim environments

given that i was having some problems with this before, and i'm just
about to upgrade to the 1.62.4 stylesheets, what's the recommended way to
add a small indent to my verbatim environments?  the previous problem was
that the indent i was trying to add did not take into account whether the
verbatim element was already a child element and therefore already
indented.  so which is the correct approach?

<!--
<xsl:attribute-set name="monospace.verbatim.properties">
 <xsl:attribute name="margin-left">0.25in</xsl:attribute>
</xsl:attribute-set>
-->

<!--
<xsl:attribute-set name="monospace.verbatim.properties">
 <xsl:attribute name="start-indent">body-start() + 0.25in</xsl:attribute>
</xsl:attribute-set>
-->

rday