[XeTeX] Spacing of bold text

[Benct Philip Jonsson]

Two questions:
1) What's the tradition wrt the spacing of bold-type text?
    Was it set with more spacing than medium-weight text?
2) Is it only me[^1] or does bold text in most fonts become
    more readable if some spacing is added?[^2]


[^1]: I have a problem with peripheral vision so it might
       very well be just me.  However since my field of vision
       is narrow I typically want blocks of text to be narrower,
       not wider.

[^2]: e.g. \setmainfont[BoldFeatures={LetterSpace=2}]{Favorite}

/BP