Well, I had 10 GU10 50W light bulbs in my kitchen. i replaced them for LEDs, so now it is 25W instead of 0.5kW of lights.
Looking on the net, it says the Gigbar 2 is 6x 3.5W Quad-colour LEDs + Strobe: 4x 1.8W Dual-colour LEDs plus 6x 6W LEDs. So that would be 60W if they were all on at the same time (ie, all on bright white and not cycling colours).
Yes, but it is complicated and you would need to know what your duty cycle of your amp use is. I mean if you are playing a thrash song with bass / drums / vocals in the PA, you would use a lot more power than if you are were playing 7 nation army for instance, which is 80% gap.
Next time you have a gig measure it, and then you will know for the following sale!