\advance\dimen@ \ht\ifvoid\LT@firsthead\LT@head\else\LT@firsthead\fi
\advance\dimen@ \dp\ifvoid\LT@firsthead\LT@head\else\LT@firsthead\fi
\advance\dimen@ \ht\LT@foot
- \advance\dimen@ \LTextracouponspace
\dimen@ii\vfuzz
\vfuzz\maxdimen
\setbox\tw@\copy\z@