The actual meat and potatoes of the unit is organized into "quads", ( equivalent to “fire-teams” of four each in military parlance, but not an appropriate term given our missions), commanded by a Lieutenant SG with a mix of Lieutenant JGs, Warrant-Officers, or other NCOs under them. Quads are trained to operate independently as tightly integrated teams but can be grouped together for larger missions. This provides a minimum unit for mutual support: four people assigned to an area or mission (possibly with a Deputy attached for direction) who can then operate as a pair of pairs either within sight or radio of each other. It works equally well for neighborhood door-to-door sweeps, checkpoints, SAR, or scout-sniper teams.
We don't ever want to perform an activity as less than a pair. The buddy system provides someone to watch your back and for mutual support when something goes wrong. But partnering also means you have a witness of your actions and, because you have a witness, you are less likely to break the rules or take shortcuts in sight of your partner. This is why police organizations always used partners prior to getting their budgets slashed. Quads are also easy to assign to vehicles for transport.
Another aspect of this is that we can form quads of people who can frequently get together for training, equipment maintenance, etc., gathering quads together slightly less often for unit tactics. The same structure then translates to who you automatically muster with in an emergency to either handle your local area or gather into larger units. Small units for local training plus shared doctrine for larger maneuvers works very well for the weekend-warrior type situation. Because officer turn-over should be lower than for professional units (platoon and company-level command in the US military rotates on a 12-18 month basis), the end-level of training and readiness can actually be higher in volunteer units.