Well, all I can offer are the typical variants. To some it’s just white skin, Caucasian facial features (arched noses, thin lips, high narrow cheekbones), lighter hair colors preferred etcetera.
Then you have the whole trope of blonde hair, blue eyes, very fair skin. The Germanic/Nord look.
And then you have some that will settle with anyone European as long as they aren’t too dark.
Those are some of the ones I’m familiar with. You have various ideas of “whiteness” among white supremacists just as you do methods. You have the isolationist “displace the minorities” types and then the radical gas chamber and firing squad ones. While one white supremacist will tolerate or even “accept” an Italian or Spaniard for example another white supremacist would call them an ape/lesser human.





