I've only banded whole horns. Even if you band the horn off all of the way it can still grow back but usually as a scur. If I were you I'd band the whole horn. Doesn't make sense to band half of it...at least with scurs most of the time you can trim it or the goats knock them off themselves.
Depending on how far down you band I think it would work. I can't really see doing it, i'm sure the horn would grow really weird after. If your going to do it i'd just go all the way and take the whole horn off.