Hi,
No, we aren't too worried about absolute values, since the "final variable" is the 1800 C heat in the furnace.

The "coil" is wound as two coils, mounted one on each side of the (3 inch x 1/2 inch 75 x 12mm) busbars. Each coil has two layers, wound in opposite senses.

This one is another idea down to my father, not mine, but its elegant isn't it ?

Steve