I have some marine type dc (12-15v) high flux led lights and need recommendations for adjusting the voltage across a range of 13.2vdc (my regulated power supply output) to 9vdc (the zero point for light output) to allow dimming. I have been told pwm type dc dimmers will not work with the high flux leds. Please help. I think I can use a rheostat, but am clueless as to how to select one, or where to purchase same to handle a circuit with a 2 amp load (8 lights with .25amp rating each wired in paralell).