Hub shaft and face measurements: 

1) AC/Delco - 
Hubs_compared1.jpg 

    Shaft I.D. - 29.5mm 
    Shaft O.D. - 42.7mm 
    Thickness - 6.6mm 
    Face - 7.5mm 

2) SKF latest that broke - 
Hubs_compared12.jpg 

    Shaft I.D. - 29.4mm 
    Shaft O.D. - 33.8mm 
    Thickness - 2.2mm 
    Face - 10.5mm 

3) BCA new unused - 
Hubs_compared9.jpg 

    Shaft I.D. - 29.4mm 
    Shaft O.D. - 39.2mm 
    Thickness - 4.9mm 
    Face - 8.0mm 

4) SKF Achieva - 
Hubs_compared3.jpg 

    Shaft I.D. - 29.7mm 
    Shaft O.D. - 38.9mm 
    Thickness - 4.6mm 
    Face - 10.7mm 
    Race (pressed on shaft) - 44.8 

Okay here's what I've discovered. Although the new Fiero SKF looked to 
be a better hub based on the hub face, it turns out that the shaft is 
too thin, 2.2mm. The AC/Delco hubs have the thickest shaft, 6.6mm, this 
is the shaft wall thickness near the outer race. The outer race is part 
of the hub and is not separate or pressed on providing the greatest 
strength where the shaft needs it. The BCA was measured without it being 
torn down. So I don't know how the shaft and outer race are assembled. 
The face was only slightly thicker than the AC/Delco. The SKF Achieva 
hub has a thicker hub shaft, 4.6mm. It also has the thickest face with 
round access whole instead of a U access point in the AC/Delco and other 
Fiero hubs. 

Now I'm still concerned about the shaft thickness. The outer race is 
pressed on to the hub and butts up against the face. This might be 
enough but I'm not sure. I'm picking up some additional hubs from our 
AC/Delco source to do a comparison on them. I'll update you as I find 
additional information. 

I took a brand new SKF Achieva hub apart and did the measurements.