I hope like your Iwata Eclipse HP-CS, I like mine.
I think lots of folks when starting out with a double action airbrush think that airflow can be controlled with how far the trigger is pushed down. That confused me at the beginning.
The trigger up/down is meant as an airflow on/off switch only. It is meant to be either up or down. Airflow is controlled by the pressure reguator. Paint flow is controlled by pulling the trigger back or forward.
I hope this helps and makes sense.
There is an order to trigger control on a double action airbrush.
1. Push down trigger (start airflow)
2. Pull back trigger/lever (start/control paint flow)
3. Push trigger forward when done (stop paint flow)
4. Release trigger (let spring push it up, to stop airflow)
Believe it or not, failure to do it this way can make dry tip worse when using some acrylics. I can't remember where I learned this, might have been Don Wheeler's site.
Edit: You may have already known all of this. On reading your question, I thought you expected more trigger travel to be able to control airflow. If I guessed wrong, didn't mean to.