You could use MTH 6 volt bulbs or LEDs. I would also recommend 3mm LEDs as they don't get hot. Just have to watch the polarity or they won't light. I like the super bright warm white ones.
( Add around 300 ohm resistors in the line too for PS2. Lower number makes the lights even brighter.)
You should post this in the DCS forum for more help from the techs.