Eliminate topspace and bottomspace in ConTeXt

Eliminate topspace and bottomspace in ConTeXt

Background
Looking to put the page number flush to the bottom of the page using
ConTeXt. The key lines in the Minimum Working Example (MWE) below are:
\setuplayout[
topspace=\zeropoint,
%bottomspace=\zeropoint,
]
I thought that by eliminating topspace and eliminating bottomspace the
page's text height would automatically be calculated to fill the entire
area.
Minimum Working Example
An example that shows what I'm trying to achieve:
\setuppapersize[letter][letter]
\setuplayout[
topspace=\zeropoint,
%bottomspace=\zeropoint,
]
\showframe
% Use roman numerals for the front matter
\definestructureconversionset[frontpart:pagenumber] [] [romannumerals]
\setuppagenumbering[location={footer,right},alternative=singlesided]
\starttext
\startfrontmatter
\setuppagenumbering[conversion=romannumerals]
\setcounter[userpage][1]
% Table of Contents
\completecontent
\stopfrontmatter
\startbodymatter
\setuppagenumbering[conversion=numbers]
\setcounter[userpage][2]
\startchapter[
title={chapter},
reference=sec:chapter,
]
\startsection[
title={section},
reference=sec:section,
]
\stopsection
\stopchapter
\stopbodymatter
\stoptext
Question
How would you move the page number to the very bottom of the page, as
shown in the following image:

Is this something that needs a dynamic layer?
Related
Set layout for the first page of Chapters in ConTeXt
ConTeXt MarkIV: Pagenumber in layer not working
http://wiki.contextgarden.net/Layout