I say go with a Kayfun Lite clone. Don't even worry about adjustable airflow you will leave it wide open all the time anyway, and later will probably want to drill out the air flow even bigger.
Also find a Kayfun fill tool to go along with it, so you don't have to dump the juice to get to your coil.
edit: BTW I have an Orchid base I use with a standard bell cap and Kayfun 4 chamber. Absolutely love it, but coming from a Nautilus, it just may be too much for ya.