I'm just an idiot civilian, but too me that's determined by dispersion and doctrine. My thinking, in laymans terms:
Assuming a 90 degree arc of responsibility, your single vehicle can provide coverage for 22.6km of front.
Assuming you want it to be able to hit targets at some sort of standoff distance in front of the supported troops (let's say 4k) across the entire arc, step that in and you've got your supported troops with frontage of 17km.
To my uninformed sense that seems like an arty weapon held at Bde at minimum.
I don't agree that the launchers themselves would be able to deny territory. But could a battery (or even a detachment)go a long way to helping a LAV + Medium Cavalry Capability equipped CMBG be able to be more effective in a widely dispersed screen/guard?