A common fallacy is the more the better. I've fallen into the trap many times. I have a set of Mole Richardson Mini Moles which are 200 watts. They're fresnel lights and they're my favorites. I shoot mainly tabletop and portraits and 200 watts is more than enough for me. On a recent assignment, I had to use some scrims to dim them over a stop to balance them with the ambient lighting. I don't know what you shoot nor what your approach is, but use your lights a bit and come to your conclusion through experience. If your lights permit, you might be able to up the wattage just by changing the bulb. But read the instructions first.