I'm not a typographer (intelligent or otherwise), but I'm having a tough time seeing how Section 2.10 *requires* fonts and rendering engines to give a space-plus-combining-diacritic combination the exact minimum width of the diacritic alone, or to leave equal space before and after such a combination. All I think it is saying is that, for example, the combination i-plus-tilde may be wider than i alone, because tilde is wider than i.
Considering that one approach is to use opentype to map a letter plus diacritical to a single glyph, an obvious solution would be to include space + diacritical combos in that table. An important font issue, but a font issue nonetheless.
-- Curtis Clark http://www.csupomona.edu/~jcclark/ Mockingbird Font Works http://www.mockfont.com/
