Do you have the camera and housing already? Because they are very scarce these days.
I shoot just the camera and housing, no added gadgets.
You will find that taking 50-150 pics a day will greatly increase your learning curve. Be ruthless, dont settle on an "ok" photo, be harsh on yourself and the pics will improve quickly.
For freediving check out Issue 19 of UWP.
http://www.uwpmag.com/
Ive been using this setup for 1.5 years for some nice results.
