I agree Richard, but I wouldn't be welding steel with 8 ltrs/min more like 15 ltrs/min which is around what I'd use for steelIt’s very dependent on shroud size.
With aluminium you are welding in spray or pulse. It doesn’t really work in dip so your using bigger duty torches which usually means bigger shrouds. I’d say hood is on the money 15-18lpm really