The idea of a bellwether precinct is that whoever wins it wins the larger jurisdiction in question. My calculations are that the following precincts are the best bellwethers for Kalamazoo County.
Comstock 6 (Gull Road area)
Cooper 3 (Riverview Drive area)
Kalamazoo Township 6 (Grand Prairie area) (presidential years only)
Kalamazoo Township 9 (Northwest)
Texas 3 (KVCC)
Portage 15 (state streets)
Portage 20 (W Milham)