Is there one parameter that you can look at to determine toe forgiveness of a golf club?
The longer the C-Dimension, which is the measurement from the hosel centerline out to the horizontal center of gravity, the more stable an iron design will be (or the more forgiving it will be). That being said, the vertical cg also needs to be in a good position, specifically not too high, for the overall playability (forgiveness) to be considered at a high level. Combine a longer C-Dimension and a lower vertical cg, you should have a high level of stability on off center hits.
Britt Lindsey