Actually, of course, the only way to *guarantee* that readers will see the right glyphs is to chuck HTML altogether and create a PDF file.
And that's a task that needs to be approached with some care as well. The UTC and WG2 constantly get PDF documents with all the interesting glyphs trashed in them.
For the code charts, I have long given up on embedding fonts and am using a two step process of creating a PS file and using distiller.
For the PS driver I select "convert TT fonts to outline" or similar settings which extracts and embeds the specific outline information. I disable all embedding.
That makes for poorer font quality at small magnification, but absolutely guarantees that what I put together is what people see. So far, that has worked well for the purpose.
A./
