> several times in the last few years I have read in a blog or article or
> some other account, of folks using thin paring chisels honed to 20 
> degrees.

Actually, I grind almost all of my chisels to 20 degrees.  No these 
aren't
pattern makers, but bench chisels and firmers that do hard work.  
They're
a mixture of W. Butcher, D.R. Barton, and Buck Brothers mostly.  They 
seem
to thrive at 20 degrees.

For really thin shavings, I have several Berg and Sandvik chisels that I
grind to 15 degrees.  They'll take it and hold it in my experience.

Mike in Sacto