eight point fonts for the main text.
To do this, you need to hack texinfo.tex.
I can't give you an exact recipe, but the fonts are defined at the 50
lines or so starting at
\ifx\bigger\relax
\let\mainmagstep=\magstep1
\setfont\textrm\rmshape{12}{1000}
\setfont\texttt\ttshape{12}{1000}
...
You might be able to use \mainmagstep to do some of the work (setting it
to a magstep less than 1000) or maybe not, I really don't know.
You should get the latest texinfo.tex from
ftp://ftp.gnu.org/gnu/texinfo.tex before you start -- not that it will
help with this particular problem, but just on general principles.
Hope this helps,
K
