Glad to be of some help Dave.
Some reasoning behind these choices:
BB pellets at range are the smallest pellets that penetrate decently.
With round projectiles, the frontal area goes up by the square of the diameter, the weight by the cube of the diameter and the coeficient of form stays constant.
Boiled down, this means that bigger pellets have higher sectional density and ballistic coeficient, therefore they retain more velocity at range, and penetrate better. Balancing this is the thinner patterns one gets with larger shot and fewer pellets per load. If the full load (or most) of the pellets hit the target then more energy is imparted.
At 20 feet there is little difference. At 30 yards, it becomes quite significant.
This is why I really don't care what kind of shell I use in the bedroom, but deer hunting I use 000 buck. Typically you'll find 000 pellets under the hide on the far side of a deer hit broadside. 000 usually patterns better than 00 also, as long as it isn't used in too tight a choke.
BB is a good load that performs well on medium-sized varmints out in the yard yet is entirely adequate inside the house. Thus it is my 'standby' load.
Were I worried about mainly needing to engage thugs at range I'd opt for buckshot or slugs unless a rifle is handy. Same for officers who might need to take out a radiator or tires.
Hope this helps explain my rationale some. Other folks' situations will be different.