Hundred watt bulbs stablize at a resistance that burns 100 watts at the rated voltage. And at the rated watts they draw the rated current. So all that I need to do is have a long enough string to have the right voltage drop at the right power. That makes it into seventh grade math, or possibly fifth grade math. Not complex. "How many hundred watt bulbs to use 3000 watts? How many 120volt bulbs to run on 4000 volts?

 

33 1/3 bulbs to get to 4000V
33 bulbs = 3300 watts.

 

33 1/3 bulbs to get to 4000V
33 bulbs = 3300 watts.

33 x 121 volts =3993 volts=close enough
33x100w=3300 watts=a bit of margin

but with 30 bulbs the bulb voltage would be 131 volts, and the power would be a bit more. But the voltage could easily be measured and also the current and that would verify the actual power close enough. no five-digit meters required.