I was actually talking about the radius, which affects the thickness and curvature (fingers to thumb). The Classic Stingray is a completely different shape. The nut width doesn't make a difference if your LH technique is classically correct.
Model:Sabre
Neck Radius:11" (27.9cm)
Headstock Size:Only 8.25" (21cm) long
Frets:21 - High profile, wide
Neck Width:1.625" (41.3mm) at nut 2.5" (63.5mm) at last fret
Model:StingRay
Neck Radius:11" (27.9 cm)
Headstock Size:Only 8-3/4" (22.2 cm) long
Frets:21 - High profile, wide
Neck Width:1-5/8" (41.3 mm) at nut 2-1/2" (63.5 mm) at last fret; Optional "SLO Special" 1-1/2" (38.1mm) at nut 2-1/2" (63.5mm) at last fret
Model:Classic StingRay 4
Neck Radius:7.5" (19.1 cm)
Headstock Size:Only 8-1/4" (21.0 cm) long
Frets:21 - High profile, narrow width
Neck Width:1-5/8" (41.3 mm) at nut 2-1/2" (63.5 mm) at last fret
So, judging by the neck radius measurements, the Classic Stingray is thicker (fingers to thumb) than the modern neck shape and therefore more acutely rounded.