Just head over to retro rides. Pretty much every dubber over there has banded steels, you should get an idea of what you would like.
You need to decide on width like you said and also offset.
It's all down to personal preference but you should aim for something that will fit under the arches with tyeres.
Hoopdubs recently had some banded steels made, I think it was a 2" band which bought the rim a little past the arch with a little bit of dish.
Or you can have a 3.5-4" band with a very low offset and forever have trouble fouling the arches and tyres rubbing