Looking for lighter weight fins that won't make me vertcal when otherwise neutrally buoyant.
With many divers, the vertical problem is caused by the leverage of a heavy weight belt--it tends to push the legs down more than the upper torso..if this is the problem, then the solution is to carry your weight up higher --- for scuba divers, the solution is often a backplate and wing, with the backplate weighing around 10 pounds, this helps reduce the leverage by reducing the amount of weight needed on a weight belt. If more weight is needed, then there are weight pockets that can go on the body of the harness, to keep the weight over the upper torso...visit
Halcyon: Eclipse Wings AND
Halcyon: ACB Weighting Systems for a look at what I am talking about....
As to fins, if you get a good set of freediving fins like Cressi Gara's or Omer, or Picasso, your efficiency in the water will be much higher, and your ability to stay effortlessly on a "plane" ( completely flat/horizontal) will be much higher than with conventional scuba fins, or than Force or bio fins, etc.
Also, far better than the lousy weight belts sold at most scuba shops are the freedive belts--they are stretchable, so that they can be tight, but move in and out with your stomach. They can also be much more easily ditched than a normal scuba belt.
As long as you maintain a slow effortless kick with freedive fins, I see litterally no way your legs could sink.
Dan