Aerodynic...
I would start by figuring the amp draw range of the bar and go from there.
The amp draw is determined by the typa and quantity of each bulb.
An H1 bulb is 55 watts. At 12 volts it would draw 4.6 amps, at 14.4 volts it would draw 3.8 amps. A 795 bulb draws 3.5-4.2 amps.
The PAR36 bulbs come in a wide range of wattages. The model number and wattage are typically on the back of those.
The motor(s) will draw less then an amp total.
Once you find out the power draw, look for a power supply that is around 25% larger then what you need. If you are not planning on using/leaving on the alleys much then you can deduct their draw from the additional 25% but still keep the total bar draw below the max output of the supply.