Just go to a dive shop and find one that works with your mask and head. Some of the quick-releases are pretty clever now. If you pay more than $45 you're doing it wrong.
You definitely want to get away from the surface for really good shots - at least a couple of feet under to get away from the layer of particles and microbubbles that floats right under the surface. Ideally you would get even further below, but that would obviously require holding your breath. If you can get down 10-15 feet you'll be able to get some memorable shots. No strobe - you want to be as streamlined as possible so you can zip around to the right angle.
I use 3 lbs with my full 3mm, but your results may (will) vary.