Ridge Helmet Naming?

[Urselius]

Precisely my point. You can have two types based on skull construction and put all other elements down to minor variations on a theme, or you can call every minor variant its own type.

Personally I would go with basic skull construction as the basis of classification. After all the Deurne helmet is functionally more like the Deir el-Medina spangenhelm below the brow-band than it is to most of the Intercisa types, but the skull construction is the deciding factor here.