What wire gauge and insulation rating should I use for connections?

Use only copper wire with a minimum 75°C insulation rating. The wire gauge should be between 10 AWG (5.2 mm²) and 14 AWG (2.1 mm²). Terminal connector lugs are provided for spade-type terminals and each terminal screw should be tightened to 20 inch-pounds of torque. (Pages 4, 39)