A pool is actually the perfect place to dial in weighting and trim. The shallower you are, the harder it is to control your buoyancy. If you get it dialed in in less than 10 feet of water, you will be good to go in the deeper stuff.
I have weighed a few different pairs of fins in the pool, using a digital luggage scale. Size Large Dive Rite XT fins were 0.4 pounds negative. Not as "light" as, for example, Deep6 Eddy fins, but still pretty light. The same as Atomic Blades and lighter than Hollis F1 or F1 LTs.
Needless to say, they would be closer to neutral in salt water.
With my BP/W, I virtually never need to add any weight at all. But, that is because I normally use steel tanks.
If I am having an issue with my feet wanting to sink, I start by moving my tank up in the straps to as high as it will go without me hitting my head on it. If my feet still sink, then I switch to lighter* fins. If I end up with my Deep6 fins on (my lightest) and my feet still want to sink, then I put a pair of small trim weight pouches ($10 each -
DGX Gears Trim Weight Pocket (each)) on my top tank strap and put a little weight in there. Normally, I never have to go as far as adding weight.
* I say "lighter" meaning "less negatively buoyant". Lighter on land does not automatically mean they are less negative in the water.