The Kangar Subtank / top
tank is a DTL delivery device with easy open airflow that can also be used MTL by restricting airflow via the airflow controller.
One reason you're not getting suggestions you like is it seems you're looking for two completely different types of delivery devices all in one.
One that is equally as good for MTL as it is for DTL using the same replaceable head, adjusting only the airflow control. Airflow is the heads cooling system.
I've used both the smoke spirals and spirals plus delivery devices, if the kangar sub/top
tank wasn't an improvement in your opinion probably best to stick with the spirals.