I'm going to guess there were at least 2-3 of the W4 at each murder scene. I'm also guessing FR and HG were shot simultaneously by two gunmen. One on either side of their bed. The scene at Dana's was the most complicated as they had two adults and one teen to deal with, I doubt one gunman shot them all. CRsr must have had at least 2 maybe 3 of the W4 there.
I realized we can't assume one gunman killed everyone at each crime scene, it was probably a combination of gunman at each crime scene.
We know Billy, Jake and G4 had favored guns. Do we have enough autopsy information to deduce what guns(caliber bullets) were used to kill each victim?