setting default page size in ConTeXt?

[Thomas Porter <txporter@mindspring.com>]

Well, since the newest context did not like me running pdftex 13.d, and I got
weird '...doclipping...' error messages on my test file, I re-installed my
tetex 1.0 RPM's on my redhat system, and started going to work getting it set
up again:

-set the default papersize in xdvi and dvips to US letter.

-got my modes and default printer set.

-added etex to the ConTeXt paths in texmf.cnf

-uncommented out the ConTeXt formats in fmtutil.cnf.

-created the ConTeXt formats for en nl and de.

-changed the default papersize in pdftex.cfg from A4 to US letter

After all that, I can use pdflatex to produce 8.5 x 11 documents from LaTeX
source, but running texexec --pdf on ctest.tex (included below) results in an
A4 page size as reported by acroread.  I am stumped and have not found a place
to set paper size in ConTeXt.

ctest.tex:

\starttext
\startstandardmakeup
\midaligned{How to make a Context document.}
\midaligned{by}
\midaligned{Tom Porter}
\stopstandardmakeup
\completecontent
\chapter{Introduction}
Well, this is pretty neat, if it works.  I will see how it does in just a minute.
I really need to determine if this is a useful tool, or if it is YALT. \index{YALT} ...
\chapter{One Chapter}
\section[firstsection]{The first section}
It seems that this does work, somewhat.  I guess it might work for me.  I sure hope so.
\section{The second section}
\subsection{the first sub section}
Perhaps it will not be another YALT afterall.  BTW that means Yet Another Latex Tool. \index{YALT} ...
\subsection{the second sub section}
It is hard to think of silly text to put into this kind of thing after a while.  I hope this ends up going to more than one page.
\section{The third section}
Here is more of my text as requested in the sample.
\chapter{Another Chapter}
Now, here is more text.
\chapter[lastchapter]{The Last Chapter}
This is the last of my text.  I hope it is enough.
\completeindex
\stoptext

-- 
Tom Porter                                       txporter@mindspring.com
------------------------------------------------------------------------
"On two occasions I have been asked [by members of Parliament], 
'Pray, Mr. Babbage, if you put into the machine wrong figures, will 
the right answers come out?'  I am not able rightly to apprehend the 
kind of confusion of ideas that could provoke such a question."