[metapost] Problem with defaultscale

[Oliver Buerschaper]

> Defaultscale only works for string labels, not for btex ... etex
> labels. But the good news is that scaling a btex ... etex label
> is really simple also:
>
>   label(btex Hallo $\sum$ etex scaled 6, origin);

One more thing perhaps … I just realized that this scales the text  
*after* TeX typeset it, doesn't it? Now how can I make TeX itself  
typeset the text at the right font size (especially math) such that I  
get the opticals right? Would I have to use a preamble like the one  
Laurence suggested?

Oliver