[NTG-context] Help on tweaking alignment, page numbers and ToC

[Nicola]

Thank Pablo, Wolfgang,
I have learned more by reading your replies than by myself in the rest
of the afternoon. Just one more thing:

>>> 1. Increase the space between Roman numbers and titles in the ToC.
>>
>> distance with dimension is the key in \setuplist.
>
> Correct but it's also important to set "width" to a value which is large
> enough to fit the number.

Chapters in the front matter have no number, so the Preface gets aligned
with the numbers of the other chapters:

Preface
   I     XYZ
  ...
VIII     XYZ
  ...

I'd prefer all the titles to be aligned:

         Preface
   I     XYZ
  ...
VIII     XYZ
  ...

I have tried to do my homework by playing with \setuphead, but I am
afraid I need your help on this.

Nicola