All the speakers, except for the LF one (s) should be of the same type, power, dimension, etc. Mixing, vocals are center, music L&R, reverb and other effects are on your surrounds. LF frequency - bass, etc., on the .1. This is for music. For video, voice on center; music and effects on L & R; effects, i. e., atmosphere, fly bys, etc., on surround. LF rumbles, etc on .1.
What will be you final master?