I've got a slightly different question over this alignment problem.
I have a 2.2 JTS Brera on standard 17" wheels. When I bought it new in 2006 it presumably came with the factory settings which my handbook quote as "half toe in 8' plus or minus 4'."(There is definitely no minus sign in front of the 8' although there is for the 3.2 version on the same page, so I presume this is a printing error.)
Suffice to say, the inners on the front tyres scrubbed off after a few thousand miles. In those days there was no mention of resetting the alignment, just countless complaining posts on the official ARUK Cloverleaf website.
Eventually, suggestions to use a zero setting filtered through and the tyre wear issue was resolved.
My question is, as I need the alignment resetting after fitting new track rod ends what setting should I use. My Brera barely does 2,000 miles a year now so tyre wear isn't really an issue any more, whereas steering vagueness, especially when compared to my other cars, both fitted with the much maligned electric power steering systems, is very noticeable.
I don't want to go to the full -8' but am I being too simplistic in thinking -4' each wheel would be the obvious compromise?