Hi,

in current luatex snapshot
(LuaTeX, Version snapshot-0.30.0-2008093012, ConTeXt  ver: 2008.10.03  
23:45)
hz seems to be broken (unless I made a typo here):


\definefontfeature[hz][default] 
[protrusion=pure,expansion=quality,mode=node,script=latn]
\usetypescript[postscript]
\definetypeface[postscript][rm][serif][times][default][features=hz]

\setupbodyfont[postscript,10pt] \setupinterlinespace[line=12pt]
\setupalign[line,block,hanging,hz]

\starttext

\showframe

\input tufte

\stoptext