30cm^2 is puny, and you will definitely not be able to find rabbits at 300meters. That’s almost like a laser beam.
The hotspot is where most of the beam is concentrated, in the middle of the beam and the spill is the light coming out the side.
The collimator head is specifically for the 7g5v2, and is the same as any aspheric lens which turns the light into almost a laser. It eliminates all spill and focuses about 50-80% (depending on lens size) of the total light into one hotspot.
here are pictures of a STL-V2, 7g5v2, and 7g5v2 with collimator lens attached.