You could easily get away with 22 or 24 Gauge wire for the LEDS. They only take 0.020 Amps each.

150 ohm resistor will work great when using power from your main battery - 6v.

As far as a switch is concerned the motor will draw as many amps as it needs to in order to spin the prop. A larger prop will draw more amps. I've logged the 7.2v Graupner 600 motor at about 21A - 26A on 6 cells pushing a mono. It gets pretty warm at that rate.

Ryan