On Fri 18 Nov 2011, Hans Hagen wrote:

so, best is that those asking for it come up with a list of issues:

which symbols need this option, is it language related or whatever,

so that i can do them all at once. We can already have different

mapping sets so spacing could be part of that.

I don't personally have a need for units in the foreseeable future (I
was just nitpicking with Robin about spacing) so feel free to ignore
any of my suggestions, but I think the summary so far would be:

1. Spacing for almost all SI units should be the same and doesn't
  need special cases.

2. Geographical degrees/minutes/seconds should have no spaces.

3. Spacing for degrees temperature varies according to different style 
  guides -- both before and after the ° -- so ideally it would be
  possible to set these independently of the rest of the units.

For my own part I would add:

4. SI unit abbreviations are mostly capital letters, and look (to me)
  strange with old-style figures. I have seen books which used 
  old-style figures for page numbers, years, etc. but switched to
  lining figures when a unit was involved; this is also what I did
  in my thesis. So I think it would be useful to allow an automatic
  switch to lining figures to be configured when typesetting a unit.

Pont