The handbook for my '67 Duetto is also 24/26 psi.
I have had the center of tires wear - from over inflation. Note that many cars have a different pressure spec for light/max cargo load (max GVWR), including my 4200 pound Mercedes. I've had tires wear in the center when inflated for trailer towing (not an Alfa) - more load strength from the higher pressure, but worse contact patch uniformity.
The Tire and Rim Association (http://www.us-tra.org/
) has recommendations for rims and tire pressures that differ from the auto manufactures. They are oriented to maximum safety (tire frailure from overloading is the major problem they see); auto makers balance comfort, tire wear, performance and handling, rain, dry, etc. for their recommendations, adn different makers have different balance points.
For racing with somewhat larger than stock tires, I've ended up with higher tire pressure than the book values. On the track, its all about lap times. Use a tire pyrometer to measure across the tread, adjust pressure (and about a hundred other variables) to get uniform temp, or at least similar right and left side temps. I've used pressures in the 30's (32 to 38) for 205/60/14 Kuhmos or Hoosiers, lower for my old favorite A008's.
I have several high quality (means expensive) tire guages, and some cheep ones. All sorts of readings from any of them. The only thing that matters is that you can get the same reading from one guage several times, over several days. (That's hard enough). I've found 5 psi variations among very good guages with careful techniques.
How you take a tire pressure reading can affect the pressure reading by several psi, so you must establish a repeatable technique.
Cold or warm maters. Before or during runs especially affects what the number is. I have tires that read up to 8 psi higher after a few laps. No extra air added. Tha means how you drive matters too.
Some racers are now using Nitrogen gas to inflate their tires. Better heat transfer, less sensitive to tire and track temperature.
And all this discussion about the difference between 26 and 32 psi! That's less than one cu ft of AIR!!!