I still occasionally use an old Aspire ET-S glassomizer with the new BVC coil and never had a gurgling or leaking problem. It's a really good vape nearly as good as the Nautilus. I vape 30 pg and 70 vg which works well with the BVC coils. If you vape very thin eliquids this might be getting too much juice into the coil chamber thus causing the gurgling. More than likely though the problem is too tight a draw which also gets too much juice into the coil chamber. I believe that you need more airflow but I am not experienced enough to tell you how to increase the airflow. Maybe one of our more seasoned members can help with how to increase the airflow.
As a last resort you might consider checking with your local shop for a solution.
Isn't that the beauty of the Nautilus? That you can easily adjust the airflow?
best regards, larry mac