16 or 20mm band

I've never experienced what you're talking about. But then I tend to take my time and do things right.

Maybe Hau, or others who have used double band closed muzzle Rob Allen(or other pipe gun) can chime in.

Double bands are a potential tangling problem when you are using a reel. With a float line there's no difference IMO.

Never had tangles but I always used open muzzles.